diff --git a/services/frontend/pkg/config/config.go b/services/frontend/pkg/config/config.go
index e2bfb6a67b..6ff194bde0 100644
--- a/services/frontend/pkg/config/config.go
+++ b/services/frontend/pkg/config/config.go
@@ -158,6 +158,8 @@ type OCDav struct {
 	// PublicURL used to redirect /s/{token} URLs to
 	PublicURL string `yaml:"public_url" env:"OC_URL;OCDAV_PUBLIC_URL;FRONTENT_OCDAV_PUBLIC_URL" desc:"URL where OpenCloud is reachable for users." introductionVersion:"1.0.0"`
 
+	ThumbnailSourceTypes []string `yaml:"thumbnail_source_types" env:"OC_THUMBNAIL_SOURCE_TYPES;FRONTEND_THUMBNAIL_SOURCE_TYPES" desc:"Additional mime types oc:has-preview is answered with 1 for, the same list the webdav service attempts previews for. The types the build ships are included; this only adds to them." introductionVersion:"%%NEXT%%"`
+
 	// Insecure certificates allowed when making requests to the gateway
 	Insecure      bool `yaml:"insecure" env:"OC_INSECURE;OCDAV_INSECURE;FRONTENT_OCDAV_INSECURE" desc:"Allow insecure connections to the GATEWAY service." introductionVersion:"1.0.0"`
 	EnableHTTPTPC bool `yaml:"enable_http_tpc" env:"OCDAV_ENABLE_HTTP_TPC;FRONTENT_OCDAV_ENABLE_HTTP_TPC" desc:"Enable HTTP / WebDAV Third-Party-Copy support." introductionVersion:"6.0.0"`
diff --git a/services/frontend/pkg/revaconfig/config.go b/services/frontend/pkg/revaconfig/config.go
index afa7018f8b..611a269326 100644
--- a/services/frontend/pkg/revaconfig/config.go
+++ b/services/frontend/pkg/revaconfig/config.go
@@ -15,6 +15,7 @@ import (
 	"github.com/opencloud-eu/opencloud/pkg/log"
 	"github.com/opencloud-eu/opencloud/pkg/version"
 	"github.com/opencloud-eu/opencloud/services/frontend/pkg/config"
+	"github.com/opencloud-eu/opencloud/services/webdav/pkg/thumbnail"
 )
 
 // FrontendConfigFromStruct will adapt an OpenCloud config struct into a reva mapstructure to start a reva service.
@@ -368,6 +369,9 @@ func FrontendConfigFromStruct(cfg *config.Config, logger log.Logger) (map[string
 					"insecure":         cfg.OCDav.Insecure,
 					"enable_http_tpc":  cfg.OCDav.EnableHTTPTPC,
 					"public_url":       cfg.OCDav.PublicURL,
+					// what oc:has-preview is answered from, the same set the
+					// webdav service attempts previews for
+					"preview_mime_types": thumbnail.NewSourceTypes(cfg.OCDav.ThumbnailSourceTypes).List(),
 					// still not supported
 					//"favorite_storage_driver":   unused,
 					//"favorite_storage_drivers":  unused,
diff --git a/services/graph/pkg/config/config.go b/services/graph/pkg/config/config.go
index a1d0b16629..2c53f7320e 100644
--- a/services/graph/pkg/config/config.go
+++ b/services/graph/pkg/config/config.go
@@ -26,13 +26,15 @@ type Config struct {
 	TokenManager  *TokenManager         `yaml:"token_manager"`
 	GRPCClientTLS *shared.GRPCClientTLS `yaml:"grpc_client_tls"`
 
-	Application       Application  `yaml:"application"`
-	Spaces            Spaces       `yaml:"spaces"`
-	Identity          Identity     `yaml:"identity"`
-	IncludeOCMSharees bool         `yaml:"include_ocm_sharees" env:"OC_ENABLE_OCM;GRAPH_INCLUDE_OCM_SHAREES" desc:"Include OCM sharees when listing users." introductionVersion:"1.0.0"`
-	Events            Events       `yaml:"events"`
-	UnifiedRoles      UnifiedRoles `yaml:"unified_roles"`
-	MaxConcurrency    int          `yaml:"max_concurrency" env:"OC_MAX_CONCURRENCY;GRAPH_MAX_CONCURRENCY" desc:"The maximum number of concurrent requests the service will handle." introductionVersion:"1.0.0"`
+	Application          Application  `yaml:"application"`
+	Spaces               Spaces       `yaml:"spaces"`
+	Identity             Identity     `yaml:"identity"`
+	IncludeOCMSharees    bool         `yaml:"include_ocm_sharees" env:"OC_ENABLE_OCM;GRAPH_INCLUDE_OCM_SHAREES" desc:"Include OCM sharees when listing users." introductionVersion:"1.0.0"`
+	Events               Events       `yaml:"events"`
+	UnifiedRoles         UnifiedRoles `yaml:"unified_roles"`
+	ThumbnailSourceTypes []string     `yaml:"thumbnail_source_types" env:"OC_THUMBNAIL_SOURCE_TYPES;GRAPH_THUMBNAIL_SOURCE_TYPES" desc:"Additional mime types a preview is announced for, the same list the webdav service attempts previews for. The types the build ships are included; this only adds to them." introductionVersion:"%%NEXT%%"`
+
+	MaxConcurrency int `yaml:"max_concurrency" env:"OC_MAX_CONCURRENCY;GRAPH_MAX_CONCURRENCY" desc:"The maximum number of concurrent requests the service will handle." introductionVersion:"1.0.0"`
 
 	Keycloak       Keycloak       `yaml:"keycloak"`
 	ServiceAccount ServiceAccount `yaml:"service_account"`
diff --git a/services/graph/pkg/service/v0/driveitems.go b/services/graph/pkg/service/v0/driveitems.go
index 167f8b1b62..88ba754796 100644
--- a/services/graph/pkg/service/v0/driveitems.go
+++ b/services/graph/pkg/service/v0/driveitems.go
@@ -351,7 +351,7 @@ func (g Graph) GetDriveItem(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if driveItemRelationExpanded(r, _expandThumbnails) {
-		setDriveItemThumbnails(driveItem, res.GetInfo(), g.config.Commons.OpenCloudURL)
+		setDriveItemThumbnails(driveItem, res.GetInfo(), g.config.Commons.OpenCloudURL, g.sourceTypes)
 	}
 
 	render.Status(r, http.StatusOK)
diff --git a/services/graph/pkg/service/v0/graph.go b/services/graph/pkg/service/v0/graph.go
index 913d2ab087..097715a472 100644
--- a/services/graph/pkg/service/v0/graph.go
+++ b/services/graph/pkg/service/v0/graph.go
@@ -27,6 +27,7 @@ import (
 	"github.com/opencloud-eu/opencloud/services/graph/pkg/errorcode"
 	"github.com/opencloud-eu/opencloud/services/graph/pkg/identity"
 	"github.com/opencloud-eu/opencloud/services/graph/pkg/metrics"
+	"github.com/opencloud-eu/opencloud/services/webdav/pkg/thumbnail"
 )
 
 // Permissions is the interface used to access the permissions service
@@ -56,6 +57,7 @@ type RoleService interface {
 // Graph defines implements the business logic for Service.
 type Graph struct {
 	BaseGraphService
+	sourceTypes              thumbnail.SourceTypes
 	mux                      *chi.Mux
 	identityBackend          identity.Backend
 	identityEducationBackend identity.EducationBackend
diff --git a/services/graph/pkg/service/v0/service.go b/services/graph/pkg/service/v0/service.go
index 347fe8ce17..03c764c5e2 100644
--- a/services/graph/pkg/service/v0/service.go
+++ b/services/graph/pkg/service/v0/service.go
@@ -22,6 +22,7 @@ import (
 	settingssvc "github.com/opencloud-eu/opencloud/protogen/gen/opencloud/services/settings/v0"
 	graphm "github.com/opencloud-eu/opencloud/services/graph/pkg/middleware"
 	"github.com/opencloud-eu/opencloud/services/graph/pkg/unifiedrole"
+	"github.com/opencloud-eu/opencloud/services/webdav/pkg/thumbnail"
 )
 
 const (
@@ -183,6 +184,7 @@ func NewService(opts ...Option) (Graph, error) { //nolint:maintidx
 
 	svc := Graph{
 		BaseGraphService:         baseGraphService,
+		sourceTypes:              thumbnail.NewSourceTypes(options.Config.ThumbnailSourceTypes),
 		mux:                      m,
 		specialDriveItemsCache:   spacePropertiesCache,
 		eventsPublisher:          options.EventsPublisher,
diff --git a/services/graph/pkg/service/v0/sharedbyme.go b/services/graph/pkg/service/v0/sharedbyme.go
index cc61df8b75..011bf94d80 100644
--- a/services/graph/pkg/service/v0/sharedbyme.go
+++ b/services/graph/pkg/service/v0/sharedbyme.go
@@ -42,7 +42,7 @@ func (g Graph) GetSharedByMe(w http.ResponseWriter, r *http.Request) {
 	expandThumbnails := strings.Contains(expand, "thumbnails")
 	if expandThumbnails {
 		for k, item := range driveItems {
-			setShareThumbnails(&item, item.GetId(), g.config.Commons.OpenCloudURL)
+			setShareThumbnails(&item, item.GetId(), g.config.Commons.OpenCloudURL, g.sourceTypes)
 			driveItems[k] = item
 		}
 	}
diff --git a/services/graph/pkg/service/v0/sharedwithme.go b/services/graph/pkg/service/v0/sharedwithme.go
index 87aa96a887..6f16195db1 100644
--- a/services/graph/pkg/service/v0/sharedwithme.go
+++ b/services/graph/pkg/service/v0/sharedwithme.go
@@ -71,7 +71,7 @@ func (g Graph) listSharedWithMe(ctx context.Context, expandThumbnails bool) ([]l
 
 	if expandThumbnails {
 		for k, item := range driveItems {
-			setShareThumbnails(&item, item.RemoteItem.GetId(), g.config.Commons.OpenCloudURL)
+			setShareThumbnails(&item, item.RemoteItem.GetId(), g.config.Commons.OpenCloudURL, g.sourceTypes)
 			driveItems[k] = item
 		}
 	}
diff --git a/services/graph/pkg/service/v0/thumbnails.go b/services/graph/pkg/service/v0/thumbnails.go
index 0fc998d6b0..d5d877e740 100644
--- a/services/graph/pkg/service/v0/thumbnails.go
+++ b/services/graph/pkg/service/v0/thumbnails.go
@@ -23,20 +23,20 @@ func (g Graph) setDriveItemsThumbnails(r *http.Request, items []libregraph.Drive
 	}
 	for i := range items {
 		if i < len(infos) {
-			setDriveItemThumbnails(&items[i], infos[i], g.config.Commons.OpenCloudURL)
+			setDriveItemThumbnails(&items[i], infos[i], g.config.Commons.OpenCloudURL, g.sourceTypes)
 		}
 	}
 }
 
-func setDriveItemThumbnails(item *libregraph.DriveItem, res *provider.ResourceInfo, baseURL string) {
-	if set := previewThumbnailSet(res, baseURL); set != nil {
+func setDriveItemThumbnails(item *libregraph.DriveItem, res *provider.ResourceInfo, baseURL string, sourceTypes thumbnail.SourceTypes) {
+	if set := previewThumbnailSet(res, baseURL, sourceTypes); set != nil {
 		item.SetThumbnails([]libregraph.ThumbnailSet{*set})
 	}
 }
 
 // previewThumbnailSet returns nil when the thumbnailer cannot render the resource.
-func previewThumbnailSet(res *provider.ResourceInfo, baseURL string) *libregraph.ThumbnailSet {
-	if !thumbnail.IsMimeTypeSupported(res.GetMimeType()) {
+func previewThumbnailSet(res *provider.ResourceInfo, baseURL string, sourceTypes thumbnail.SourceTypes) *libregraph.ThumbnailSet {
+	if !sourceTypes.Supports(res.GetMimeType()) {
 		return nil
 	}
 	return thumbnailSetFor(baseURL, storagespace.FormatResourceID(res.GetId()))
@@ -59,9 +59,9 @@ func previewThumbnail(base string, box int32) *libregraph.Thumbnail {
 
 // setShareThumbnails works off the driveItem, the share listings have no resource
 // info. The id comes separately, a received share carries it on its remote item.
-func setShareThumbnails(item *libregraph.DriveItem, itemID, baseURL string) {
+func setShareThumbnails(item *libregraph.DriveItem, itemID, baseURL string, sourceTypes thumbnail.SourceTypes) {
 	mimeType := item.GetFile().MimeType
-	if itemID == "" || mimeType == nil || !thumbnail.IsMimeTypeSupported(*mimeType) {
+	if itemID == "" || mimeType == nil || !sourceTypes.Supports(*mimeType) {
 		return
 	}
 	item.SetThumbnails([]libregraph.ThumbnailSet{*thumbnailSetFor(baseURL, itemID)})
diff --git a/services/webdav/pkg/config/config.go b/services/webdav/pkg/config/config.go
index 3cc9f8d242..f151b305be 100644
--- a/services/webdav/pkg/config/config.go
+++ b/services/webdav/pkg/config/config.go
@@ -39,6 +39,8 @@ type Config struct {
 	ThumbnailCacheS3Endpoint  string   `yaml:"thumbnail_cache_s3_endpoint" env:"WEBDAV_THUMBNAIL_CACHE_S3_ENDPOINT" desc:"S3 endpoint URL (for MinIO or compatible services) when ThumbnailCacheBackend is 's3'." introductionVersion:"%%NEXT%%"`
 	ThumbnailCacheS3AccessKey string   `yaml:"thumbnail_cache_s3_access_key" env:"WEBDAV_THUMBNAIL_CACHE_S3_ACCESS_KEY" desc:"S3 access key for thumbnail cache authentication." introductionVersion:"%%NEXT%%"`
 	ThumbnailCacheS3SecretKey string   `yaml:"thumbnail_cache_s3_secret_key" env:"WEBDAV_THUMBNAIL_CACHE_S3_SECRET_KEY" desc:"S3 secret key for thumbnail cache authentication." introductionVersion:"%%NEXT%%"`
+	ThumbnailSourceTypes      []string `yaml:"thumbnail_source_types" env:"OC_THUMBNAIL_SOURCE_TYPES;WEBDAV_THUMBNAIL_SOURCE_TYPES" desc:"Additional mime types a preview is announced and attempted for, e.g. image/vnd.microsoft.icon for a generator that reads icons. The types the build ships are included; this only adds to them. A type the running generator cannot read answers 404." introductionVersion:"%%NEXT%%"`
+
 	ThumbnailGeneratorFormats []string `yaml:"thumbnail_generator_formats" env:"OC_THUMBNAIL_GENERATOR_FORMATS;WEBDAV_THUMBNAIL_GENERATOR_FORMATS" desc:"The formats the thumbnail generator writes, as mime:format entries, e.g. image/webp:webp. The format is the name the generator's own format filter uses. A type that is not listed is one the generator cannot write, and a thumbnail mapped to it becomes a JPEG instead." introductionVersion:"%%NEXT%%"`
 	ThumbnailTypeMapping      []string `yaml:"thumbnail_type_mapping" env:"OC_THUMBNAIL_TYPE_MAPPING;WEBDAV_THUMBNAIL_TYPE_MAPPING" desc:"The type a thumbnail is written in, per type of the image it is made from, as mime:mime entries, e.g. image/vnd.microsoft.icon:image/png. The target is asked for by the name WEBDAV_THUMBNAIL_GENERATOR_FORMATS gives it. A type that is not listed, and one whose target the generator cannot write, becomes a JPEG." introductionVersion:"%%NEXT%%"`
 
diff --git a/services/webdav/pkg/service/v0/search.go b/services/webdav/pkg/service/v0/search.go
index 59739317f7..7412d21f4e 100644
--- a/services/webdav/pkg/service/v0/search.go
+++ b/services/webdav/pkg/service/v0/search.go
@@ -117,7 +117,7 @@ func (g Webdav) Search(w http.ResponseWriter, r *http.Request) {
 
 func (g Webdav) sendSearchResponse(davPrefix string, rsp *searchsvc.SearchResponse, w http.ResponseWriter, r *http.Request, user *userv1beta1.User) {
 	logger := g.log.SubloggerWithRequestID(r.Context())
-	responsesXML, err := multistatusResponse(r.Context(), davPrefix, g.config.OpenCloudPublicURL, rsp.Matches, user)
+	responsesXML, err := multistatusResponse(r.Context(), davPrefix, g.config.OpenCloudPublicURL, rsp.Matches, user, g.sourceTypes)
 	if err != nil {
 		logger.Error().Err(err).Msg("error formatting propfind")
 		w.WriteHeader(http.StatusInternalServerError)
@@ -135,10 +135,10 @@ func (g Webdav) sendSearchResponse(davPrefix string, rsp *searchsvc.SearchRespon
 }
 
 // multistatusResponse converts a list of matches into a multistatus response string
-func multistatusResponse(ctx context.Context, davPrefix, publicURL string, matches []*searchmsg.Match, user *userv1beta1.User) ([]byte, error) {
+func multistatusResponse(ctx context.Context, davPrefix, publicURL string, matches []*searchmsg.Match, user *userv1beta1.User, sourceTypes thumbnail.SourceTypes) ([]byte, error) {
 	responses := make([]*propfind.ResponseXML, 0, len(matches))
 	for i := range matches {
-		res, err := matchToPropResponse(ctx, davPrefix, publicURL, matches[i], user)
+		res, err := matchToPropResponse(ctx, davPrefix, publicURL, matches[i], user, sourceTypes)
 		if err != nil {
 			return nil, err
 		}
@@ -154,7 +154,7 @@ func multistatusResponse(ctx context.Context, davPrefix, publicURL string, match
 	return msg, nil
 }
 
-func matchToPropResponse(ctx context.Context, davPrefix, publicURL string, match *searchmsg.Match, user *userv1beta1.User) (*propfind.ResponseXML, error) {
+func matchToPropResponse(ctx context.Context, davPrefix, publicURL string, match *searchmsg.Match, user *userv1beta1.User, sourceTypes thumbnail.SourceTypes) (*propfind.ResponseXML, error) {
 	// unfortunately, search uses own versions of ResourceId and Ref. So we need to assert them here
 	var (
 		ref string
@@ -222,7 +222,7 @@ func matchToPropResponse(ctx context.Context, davPrefix, publicURL string, match
 	propstatOK.Prop = append(propstatOK.Prop, prop.Escaped("oc:permissions", match.Entity.Permissions))
 	propstatOK.Prop = append(propstatOK.Prop, prop.Escaped("oc:highlights", match.Entity.Highlights))
 	propstatOK.Prop = append(propstatOK.Prop, prop.Escaped("d:getcontenttype", match.Entity.MimeType))
-	_, isSupportedMimeType := thumbnail.SupportedMimeTypes[match.Entity.MimeType]
+	isSupportedMimeType := sourceTypes.Supports(match.Entity.MimeType)
 	if isSupportedMimeType {
 		propstatOK.Prop = append(propstatOK.Prop, prop.Escaped("oc:has-preview", "1"))
 	} else {
@@ -269,15 +269,6 @@ func matchToPropResponse(ctx context.Context, davPrefix, publicURL string, match
 	return &response, nil
 }
 
-func hasPreview(md *provider.ResourceInfo, appendToOK func(p ...prop.PropertyXML)) {
-	_, match := thumbnail.SupportedMimeTypes[md.MimeType]
-	if match {
-		appendToOK(prop.Escaped("oc:has-preview", "1"))
-	} else {
-		appendToOK(prop.Escaped("oc:has-preview", "0"))
-	}
-}
-
 type report struct {
 	SearchFiles *reportSearchFiles
 	// FilterFiles TODO add this for tag based search
diff --git a/services/webdav/pkg/service/v0/service.go b/services/webdav/pkg/service/v0/service.go
index bb1eda3a50..910460b434 100644
--- a/services/webdav/pkg/service/v0/service.go
+++ b/services/webdav/pkg/service/v0/service.go
@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"net/url"
 	"path"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -70,6 +71,8 @@ func NewService(opts ...Option) (Service, error) {
 		),
 	)
 
+	sourceTypes := thumbnail.NewSourceTypes(conf.ThumbnailSourceTypes)
+
 	tm, err := pool.StringToTLSMode(conf.GRPCClientTLS.Mode)
 	if err != nil {
 		return nil, err
@@ -88,7 +91,7 @@ func NewService(opts ...Option) (Service, error) {
 	// and its cache are never built
 	var wf *workflow.ThumbnailWorkflow
 	if !conf.DisablePreviews {
-		wf, err = newThumbnailWorkflow(conf, options.Logger, gatewaySelector)
+		wf, err = newThumbnailWorkflow(conf, sourceTypes, options.Logger, gatewaySelector)
 		if err != nil {
 			return nil, fmt.Errorf("create thumbnail workflow: %w", err)
 		}
@@ -96,6 +99,7 @@ func NewService(opts ...Option) (Service, error) {
 
 	svc := Webdav{
 		config:          conf,
+		sourceTypes:     sourceTypes,
 		log:             options.Logger,
 		mux:             m,
 		searchClient:    searchsvc.NewSearchProviderService("eu.opencloud.api.search", conf.GrpcClient),
@@ -160,7 +164,7 @@ func NewService(opts ...Option) (Service, error) {
 
 // newThumbnailWorkflow wires the preview pipeline: the generator client, the
 // cache and the gateway-backed lookups.
-func newThumbnailWorkflow(conf *config.Config, logger log.Logger, gatewaySelector pool.Selectable[gatewayv1beta1.GatewayAPIClient]) (*workflow.ThumbnailWorkflow, error) {
+func newThumbnailWorkflow(conf *config.Config, sourceTypes thumbnail.SourceTypes, logger log.Logger, gatewaySelector pool.Selectable[gatewayv1beta1.GatewayAPIClient]) (*workflow.ThumbnailWorkflow, error) {
 	genTimeout, _ := time.ParseDuration(conf.ThumbnailGeneratorTimeout)
 	if genTimeout == 0 {
 		genTimeout = 30 * time.Second
@@ -176,6 +180,12 @@ func newThumbnailWorkflow(conf *config.Config, logger log.Logger, gatewaySelecto
 		return nil, fmt.Errorf("parse max input file size: %w", err)
 	}
 
+	typeMapping := thumbnail.NewTypeMapping(conf.ThumbnailTypeMapping)
+	formats := generator.NewFormats(conf.ThumbnailGeneratorFormats)
+	if err := checkTypeMapping(typeMapping, formats); err != nil {
+		return nil, err
+	}
+
 	s3cfg := cache.BuildS3CacheConfig(
 		conf.ThumbnailCacheS3Bucket,
 		conf.ThumbnailCacheS3Region,
@@ -194,8 +204,9 @@ func newThumbnailWorkflow(conf *config.Config, logger log.Logger, gatewaySelecto
 		workflow.WithHTTPClient(httpClient),
 		workflow.WithMaxInputSize(maxInputSize),
 		workflow.WithSizes(sizes),
-		workflow.WithFormats(generator.NewFormats(conf.ThumbnailGeneratorFormats)),
-		workflow.WithTypeMapping(thumbnail.NewTypeMapping(conf.ThumbnailTypeMapping)),
+		workflow.WithSourceTypes(sourceTypes),
+		workflow.WithFormats(formats),
+		workflow.WithTypeMapping(typeMapping),
 		workflow.WithWebdavNamespace(conf.WebdavNamespace),
 		workflow.WithFontMapFile(conf.ThumbnailFontMapFile),
 		workflow.WithLogger(logger),
@@ -206,8 +217,27 @@ func newThumbnailWorkflow(conf *config.Config, logger log.Logger, gatewaySelecto
 	)
 }
 
+// checkTypeMapping refuses a mapping that asks for a type the generator has no
+// format name for: the thumbnail would silently become a JPEG instead.
+func checkTypeMapping(mapping thumbnail.TypeMapping, formats generator.Formats) error {
+	var unknown []string
+	for source, target := range mapping.Targets() {
+		if target == "" || formats.For(target) != "" {
+			continue
+		}
+		unknown = append(unknown, fmt.Sprintf("%s (mapped from %s)", target, source))
+	}
+	if len(unknown) == 0 {
+		return nil
+	}
+	sort.Strings(unknown)
+
+	return fmt.Errorf("thumbnail type mapping: no generator format for %s", strings.Join(unknown, ", "))
+}
+
 // Webdav implements the business logic for Service.
 type Webdav struct {
+	sourceTypes     thumbnail.SourceTypes
 	config          *config.Config
 	log             log.Logger
 	mux             *chi.Mux
diff --git a/services/webdav/pkg/service/v0/typemapping_test.go b/services/webdav/pkg/service/v0/typemapping_test.go
new file mode 100644
index 0000000000..c9024d95c8
--- /dev/null
+++ b/services/webdav/pkg/service/v0/typemapping_test.go
@@ -0,0 +1,48 @@
+package svc
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	"github.com/opencloud-eu/opencloud/services/webdav/pkg/generator"
+	"github.com/opencloud-eu/opencloud/services/webdav/pkg/thumbnail"
+)
+
+var _ = Describe("checkTypeMapping", func() {
+	It("accepts the defaults", func() {
+		Expect(checkTypeMapping(thumbnail.NewTypeMapping(nil), generator.NewFormats(nil))).To(Succeed())
+	})
+
+	It("accepts a pair that was configured together", func() {
+		Expect(checkTypeMapping(
+			thumbnail.NewTypeMapping([]string{"image/png:image/webp"}),
+			generator.NewFormats([]string{"image/webp:webp"}),
+		)).To(Succeed())
+	})
+
+	It("refuses a target the generator has no format for", func() {
+		err := checkTypeMapping(
+			thumbnail.NewTypeMapping([]string{"image/png:image/webp"}),
+			generator.NewFormats(nil),
+		)
+
+		Expect(err).To(MatchError(ContainSubstring("no generator format for image/webp (mapped from image/png)")))
+	})
+
+	It("names every bad entry", func() {
+		err := checkTypeMapping(
+			thumbnail.NewTypeMapping([]string{"image/png:image/avif", "image/gif:image/webp"}),
+			generator.NewFormats(nil),
+		)
+
+		Expect(err).To(MatchError(ContainSubstring("image/avif (mapped from image/png)")))
+		Expect(err).To(MatchError(ContainSubstring("image/webp (mapped from image/gif)")))
+	})
+
+	It("takes an empty target as no override", func() {
+		Expect(checkTypeMapping(
+			thumbnail.NewTypeMapping([]string{"image/png:"}),
+			generator.NewFormats(nil),
+		)).To(Succeed())
+	})
+})
diff --git a/services/webdav/pkg/thumbnail/mimetype.go b/services/webdav/pkg/thumbnail/mimetype.go
deleted file mode 100644
index 26ce86e794..0000000000
--- a/services/webdav/pkg/thumbnail/mimetype.go
+++ /dev/null
@@ -1,13 +0,0 @@
-package thumbnail
-
-import "mime"
-
-// IsMimeTypeSupported validates if the mime type is supported.
-func IsMimeTypeSupported(m string) bool {
-	mimeType, _, err := mime.ParseMediaType(m)
-	if err != nil {
-		return false
-	}
-	_, supported := SupportedMimeTypes[mimeType]
-	return supported
-}
diff --git a/services/webdav/pkg/thumbnail/mimetypes.go b/services/webdav/pkg/thumbnail/mimetypes.go
deleted file mode 100644
index d93f9a738e..0000000000
--- a/services/webdav/pkg/thumbnail/mimetypes.go
+++ /dev/null
@@ -1,24 +0,0 @@
-package thumbnail
-
-var (
-	// SupportedMimeTypes contains all mimetypes a preview is made of. Whether
-	// the generator can read one is its own business: webdav does not decode an
-	// image, so a build without libvips answers 400 for a webp instead of
-	// refusing it here.
-	SupportedMimeTypes = map[string]struct{}{
-		"image/png":                         {},
-		"image/jpg":                         {},
-		"image/jpeg":                        {},
-		"image/gif":                         {},
-		"image/bmp":                         {},
-		"image/x-ms-bmp":                    {},
-		"image/tiff":                        {},
-		"image/webp":                        {},
-		"text/plain":                        {},
-		"audio/flac":                        {},
-		"audio/mpeg":                        {},
-		"audio/ogg":                         {},
-		"application/vnd.geogebra.slides":   {},
-		"application/vnd.geogebra.pinboard": {},
-	}
-)
diff --git a/services/webdav/pkg/thumbnail/sourcetypes.go b/services/webdav/pkg/thumbnail/sourcetypes.go
new file mode 100644
index 0000000000..3495d5b011
--- /dev/null
+++ b/services/webdav/pkg/thumbnail/sourcetypes.go
@@ -0,0 +1,59 @@
+package thumbnail
+
+import (
+	"mime"
+	"strings"
+
+	thumbnails "github.com/opencloud-eu/opencloud/services/thumbnails/pkg/thumbnail"
+)
+
+// SourceTypes are the types a preview is announced and attempted for. The
+// defaults are the ones the thumbnails service compiles in, which is also where
+// reva reads them for oc:has-preview, so a build with libvips brings its extra
+// types along. Configured entries are merged on top here, per service: nobody
+// writes into that package's map.
+//
+// The list is a hint, not a verdict. The generator decides what it can really
+// read, and a source it refuses answers 404.
+type SourceTypes struct {
+	byType map[string]struct{}
+}
+
+// NewSourceTypes merges the configured types onto the compiled-in defaults.
+func NewSourceTypes(entries []string) SourceTypes {
+	t := SourceTypes{byType: make(map[string]struct{}, len(thumbnails.SupportedMimeTypes)+len(entries))}
+	for mimeType := range thumbnails.SupportedMimeTypes {
+		t.byType[mimeType] = struct{}{}
+	}
+	for _, entry := range entries {
+		if entry = strings.ToLower(strings.TrimSpace(entry)); entry != "" {
+			t.byType[entry] = struct{}{}
+		}
+	}
+
+	return t
+}
+
+// Supports reports whether a preview is made of this type.
+func (t SourceTypes) Supports(contentType string) bool {
+	parsed, _, err := mime.ParseMediaType(contentType)
+	if err != nil {
+		return false
+	}
+	_, supported := t.byType[parsed]
+
+	return supported
+}
+
+// All lists the types, so a caller can iterate them.
+func (t SourceTypes) All() map[string]struct{} { return t.byType }
+
+// List is the types as a slice, for a configuration that takes one.
+func (t SourceTypes) List() []string {
+	out := make([]string, 0, len(t.byType))
+	for mimeType := range t.byType {
+		out = append(out, mimeType)
+	}
+
+	return out
+}
diff --git a/services/webdav/pkg/thumbnail/typemapping.go b/services/webdav/pkg/thumbnail/typemapping.go
index 23e808815a..8322c7bbfe 100644
--- a/services/webdav/pkg/thumbnail/typemapping.go
+++ b/services/webdav/pkg/thumbnail/typemapping.go
@@ -54,3 +54,6 @@ func (m TypeMapping) TargetFor(contentType string) string {
 
 	return m.byType[parsed]
 }
+
+// Targets lists the type a thumbnail is written in, by source type.
+func (m TypeMapping) Targets() map[string]string { return m.byType }
diff --git a/services/webdav/pkg/thumbnail/typemapping_test.go b/services/webdav/pkg/thumbnail/typemapping_test.go
index 8ab901f56b..d3ae199300 100644
--- a/services/webdav/pkg/thumbnail/typemapping_test.go
+++ b/services/webdav/pkg/thumbnail/typemapping_test.go
@@ -12,7 +12,7 @@ var _ = Describe("TypeMapping", func() {
 	m := thumbnail.NewTypeMapping(nil)
 
 	It("answers for every type a preview is made of", func() {
-		for mimeType := range thumbnail.SupportedMimeTypes {
+		for mimeType := range thumbnail.NewSourceTypes(nil).All() {
 			Expect(m.TargetFor(mimeType)).ToNot(BeEmpty(), "%s has no output type", mimeType)
 		}
 	})
diff --git a/services/webdav/pkg/thumbnail/workflow/workflow.go b/services/webdav/pkg/thumbnail/workflow/workflow.go
index db542bfadc..fd3aadb608 100644
--- a/services/webdav/pkg/thumbnail/workflow/workflow.go
+++ b/services/webdav/pkg/thumbnail/workflow/workflow.go
@@ -139,6 +139,7 @@ type ThumbnailWorkflow struct {
 	maxInputSize   uint64
 	sizes          *thumbnail.Sizes
 	typeMapping    thumbnail.TypeMapping
+	sourceTypes    thumbnail.SourceTypes
 	formats        generator.Formats
 	webdavNS       string
 	fontMapFile    string
@@ -209,6 +210,11 @@ func WithWebdavNamespace(ns string) Option {
 	return func(w *ThumbnailWorkflow) { w.webdavNS = ns }
 }
 
+// WithSourceTypes sets the types a preview is attempted for.
+func WithSourceTypes(t thumbnail.SourceTypes) Option {
+	return func(w *ThumbnailWorkflow) { w.sourceTypes = t }
+}
+
 // WithFormats sets the formats the generator writes, by type.
 func WithFormats(f generator.Formats) Option {
 	return func(w *ThumbnailWorkflow) { w.formats = f }
@@ -298,7 +304,7 @@ func (w *ThumbnailWorkflow) Head(ctx context.Context, tr *requests.ThumbnailRequ
 		return ErrPermissionDenied
 	}
 
-	if !thumbnail.IsMimeTypeSupported(info.GetMimeType()) {
+	if !w.sourceTypes.Supports(info.GetMimeType()) {
 		return fmt.Errorf("%w: %s", ErrUnsupportedFileType, info.GetMimeType())
 	}
 
@@ -406,7 +412,7 @@ func (w *ThumbnailWorkflow) generate(ctx context.Context, ref *providerv1beta1.R
 		return nil, "", false, ErrPermissionDenied
 	}
 
-	if !thumbnail.IsMimeTypeSupported(info.GetMimeType()) {
+	if !w.sourceTypes.Supports(info.GetMimeType()) {
 		return nil, "", false, fmt.Errorf("%w: %s", ErrUnsupportedFileType, info.GetMimeType())
 	}
 
@@ -682,6 +688,12 @@ func (w *ThumbnailWorkflow) postToGenerator(ctx context.Context, url string, img
 		if httpRsp.StatusCode == http.StatusUnprocessableEntity {
 			return nil, "", ErrImageTooLarge
 		}
+		// The generator refuses what it cannot read: imagor answers 406, the
+		// built-in one 400. That is a missing preview, not a server fault, so
+		// the client gets a 404 and stops asking.
+		if httpRsp.StatusCode == http.StatusBadRequest || httpRsp.StatusCode == http.StatusNotAcceptable {
+			return nil, "", fmt.Errorf("%w: generator refused the source: %s", ErrUnsupportedFileType, strings.TrimSpace(string(respBody)))
+		}
 		return nil, "", fmt.Errorf("generator returned status %d: %s", httpRsp.StatusCode, string(respBody))
 	}
 
diff --git a/services/webdav/pkg/thumbnail/workflow/workflow_test.go b/services/webdav/pkg/thumbnail/workflow/workflow_test.go
index 65ec7c7a2a..ec17301d7c 100644
--- a/services/webdav/pkg/thumbnail/workflow/workflow_test.go
+++ b/services/webdav/pkg/thumbnail/workflow/workflow_test.go
@@ -188,6 +188,7 @@ func setupPreprocessTest(
 		WithCache(testCache),
 		WithHTTPClient(&http.Client{}),
 		WithWebdavNamespace("/users/{{.Id.OpaqueId}}"),
+		WithSourceTypes(thumbnail.NewSourceTypes(nil)),
 		WithFormats(generator.NewFormats(nil)),
 		WithTypeMapping(thumbnail.NewTypeMapping(nil)),
 		WithLogger(logger),
@@ -303,6 +304,7 @@ var _ = Describe("ThumbnailWorkflow", func() {
 			WithCache(testCache),
 			WithHTTPClient(&http.Client{}),
 			WithWebdavNamespace("/users/{{.Id.OpaqueId}}"),
+			WithSourceTypes(thumbnail.NewSourceTypes(nil)),
 			WithFormats(generator.NewFormats(nil)),
 			WithTypeMapping(thumbnail.NewTypeMapping(nil)),
 			WithLogger(logger),
@@ -1046,6 +1048,7 @@ var _ = Describe("ThumbnailWorkflow", func() {
 				WithCache(testCache),
 				WithHTTPClient(&http.Client{}),
 				WithMaxInputSize(1024),
+				WithSourceTypes(thumbnail.NewSourceTypes(nil)),
 				WithWebdavNamespace("/users/{{.Id.OpaqueId}}"),
 				WithLogger(logger),
 				WithStater(NewGatewayStater(pool.GetSelector[gatewayv1beta1.GatewayAPIClient](
diff --git a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/config/config.go b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/config/config.go
index a0f4f2477a..03e78837c5 100644
--- a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/config/config.go
+++ b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/config/config.go
@@ -37,6 +37,8 @@ type Config struct {
 	URLSigningSharedSecret string `mapstructure:"url_signing_shared_secret"`
 
 	MachineAuthAPIKey string `mapstructure:"machine_auth_apikey"`
+
+	PreviewMimeTypes []string `mapstructure:"preview_mime_types"`
 }
 
 // NameValidation is the validation configuration for file and folder names
diff --git a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/ocdav.go b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/ocdav.go
index 4746358ecb..245df52d37 100644
--- a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/ocdav.go
+++ b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/ocdav.go
@@ -35,6 +35,7 @@ import (
 	"github.com/jellydator/ttlcache/v2"
 	"github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/config"
 	"github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/net"
+	"github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/propfind"
 	"github.com/opencloud-eu/reva/v2/pkg/appctx"
 	ctxpkg "github.com/opencloud-eu/reva/v2/pkg/ctx"
 	"github.com/opencloud-eu/reva/v2/pkg/errtypes"
@@ -69,6 +70,7 @@ type svc struct {
 	userIdentifierCache *ttlcache.Cache
 	nameValidators      []Validator
 	urlSigner           signedurl.Signer
+	previewMimeTypes    map[string]struct{}
 }
 
 func (s *svc) Config() *config.Config {
@@ -128,6 +130,7 @@ func NewWith(conf *config.Config, ls LockSystem, _ *zerolog.Logger, selector poo
 		userIdentifierCache: ttlcache.NewCache(),
 		nameValidators:      ValidatorsFromConfig(conf),
 		urlSigner:           signer,
+		previewMimeTypes:    propfind.PreviewMimeTypes(conf),
 	}
 	_ = s.userIdentifierCache.SetTTL(60 * time.Second)
 
diff --git a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/propfind/propfind.go b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/propfind/propfind.go
index d3a7a24f8f..da869a905b 100644
--- a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/propfind/propfind.go
+++ b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/propfind/propfind.go
@@ -38,7 +38,6 @@ import (
 	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
 	typesv1beta1 "github.com/cs3org/go-cs3apis/cs3/types/v1beta1"
 	"github.com/iancoleman/strcase"
-	"github.com/opencloud-eu/opencloud/services/thumbnails/pkg/thumbnail"
 	"github.com/opencloud-eu/reva/v2/internal/grpc/services/storageprovider"
 	"github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/config"
 	"github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/errors"
@@ -236,19 +235,32 @@ func NewMultiStatusResponseXML() *MultiStatusResponseXML {
 
 // Handler handles propfind requests
 type Handler struct {
-	PublicURL string
-	selector  pool.Selectable[gateway.GatewayAPIClient]
-	c         *config.Config
-	urlSigner signedurl.Signer
+	PublicURL        string
+	selector         pool.Selectable[gateway.GatewayAPIClient]
+	c                *config.Config
+	urlSigner        signedurl.Signer
+	previewMimeTypes map[string]struct{}
+}
+
+// PreviewMimeTypes turns the configured list into a set, for the handlers that
+// build a propfind response themselves.
+func PreviewMimeTypes(c *config.Config) map[string]struct{} {
+	types := make(map[string]struct{}, len(c.PreviewMimeTypes))
+	for _, mimeType := range c.PreviewMimeTypes {
+		types[mimeType] = struct{}{}
+	}
+
+	return types
 }
 
 // NewHandler returns a new PropfindHandler instance
 func NewHandler(publicURL string, selector pool.Selectable[gateway.GatewayAPIClient], signer signedurl.Signer, c *config.Config) *Handler {
 	return &Handler{
-		PublicURL: publicURL,
-		selector:  selector,
-		c:         c,
-		urlSigner: signer,
+		PublicURL:        publicURL,
+		selector:         selector,
+		c:                c,
+		urlSigner:        signer,
+		previewMimeTypes: PreviewMimeTypes(c),
 	}
 }
 
@@ -521,7 +533,7 @@ func (p *Handler) propfindResponse(ctx context.Context, w http.ResponseWriter, r
 	prefer := net.ParsePrefer(r.Header.Get(net.HeaderPrefer))
 	returnMinimal := prefer[net.HeaderPreferReturn] == "minimal"
 
-	propRes, err := MultistatusResponse(ctx, &pf, resourceInfos, p.PublicURL, namespace, linkshares, returnMinimal, p.urlSigner)
+	propRes, err := MultistatusResponse(ctx, &pf, resourceInfos, p.PublicURL, namespace, linkshares, returnMinimal, p.urlSigner, p.previewMimeTypes)
 	if err != nil {
 		log.Error().Err(err).Msg("error formatting propfind")
 		w.WriteHeader(http.StatusInternalServerError)
@@ -1018,7 +1030,7 @@ func ReadPropfind(r io.Reader) (pf XML, status int, err error) {
 }
 
 // MultistatusResponse converts a list of resource infos into a multistatus response string
-func MultistatusResponse(ctx context.Context, pf *XML, mds []*provider.ResourceInfo, publicURL, ns string, linkshares map[string]struct{}, returnMinimal bool, downloadURLSigner signedurl.Signer) ([]byte, error) {
+func MultistatusResponse(ctx context.Context, pf *XML, mds []*provider.ResourceInfo, publicURL, ns string, linkshares map[string]struct{}, returnMinimal bool, downloadURLSigner signedurl.Signer, previewMimeTypes map[string]struct{}) ([]byte, error) {
 	g, ctx := errgroup.WithContext(ctx)
 
 	type work struct {
@@ -1053,7 +1065,7 @@ func MultistatusResponse(ctx context.Context, pf *XML, mds []*provider.ResourceI
 	for i := 0; i < numWorkers; i++ {
 		g.Go(func() error {
 			for work := range workChan {
-				res, err := mdToPropResponse(ctx, pf, work.info, publicURL, ns, linkshares, returnMinimal, downloadURLSigner)
+				res, err := mdToPropResponse(ctx, pf, work.info, publicURL, ns, linkshares, returnMinimal, downloadURLSigner, previewMimeTypes)
 				if err != nil {
 					return err
 				}
@@ -1094,7 +1106,7 @@ func MultistatusResponse(ctx context.Context, pf *XML, mds []*provider.ResourceI
 // mdToPropResponse converts the CS3 metadata into a webdav PropResponse
 // ns is the CS3 namespace that needs to be removed from the CS3 path before
 // prefixing it with the baseURI
-func mdToPropResponse(ctx context.Context, pf *XML, md *provider.ResourceInfo, publicURL, ns string, linkshares map[string]struct{}, returnMinimal bool, urlSigner signedurl.Signer) (*ResponseXML, error) {
+func mdToPropResponse(ctx context.Context, pf *XML, md *provider.ResourceInfo, publicURL, ns string, linkshares map[string]struct{}, returnMinimal bool, urlSigner signedurl.Signer, previewMimeTypes map[string]struct{}) (*ResponseXML, error) {
 	ctx, span := appctx.GetTracerProvider(ctx).Tracer(tracerName).Start(ctx, "md_to_prop_response")
 	span.SetAttributes(attribute.KeyValue{Key: "publicURL", Value: attribute.StringValue(publicURL)})
 	span.SetAttributes(attribute.KeyValue{Key: "ns", Value: attribute.StringValue(ns)})
@@ -1331,7 +1343,7 @@ func mdToPropResponse(ctx context.Context, pf *XML, md *provider.ResourceInfo, p
 			// directories have no preview
 			appendToNotFound(prop.NotFound("oc:has-preview"))
 		} else if md.MimeType != "" {
-			hasPreview(md, appendToOK)
+			hasPreview(md, appendToOK, previewMimeTypes)
 		}
 
 		// ls do not report any properties as missing by default
@@ -1644,7 +1656,7 @@ func mdToPropResponse(ctx context.Context, pf *XML, md *provider.ResourceInfo, p
 						// directories have no preview
 						appendToNotFound(prop.NotFound("oc:has-preview"))
 					} else if md.MimeType != "" {
-						hasPreview(md, appendToOK)
+						hasPreview(md, appendToOK, previewMimeTypes)
 					}
 				default:
 					appendToNotFound(prop.NotFound("oc:" + pf.Prop[i].Local))
@@ -1771,8 +1783,8 @@ func mdToPropResponse(ctx context.Context, pf *XML, md *provider.ResourceInfo, p
 	return &response, nil
 }
 
-func hasPreview(md *provider.ResourceInfo, appendToOK func(p ...prop.PropertyXML)) {
-	_, match := thumbnail.SupportedMimeTypes[md.MimeType]
+func hasPreview(md *provider.ResourceInfo, appendToOK func(p ...prop.PropertyXML), previewMimeTypes map[string]struct{}) {
+	_, match := previewMimeTypes[md.MimeType]
 	if match {
 		appendToOK(prop.Escaped("oc:has-preview", "1"))
 	} else {
diff --git a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/publicfile.go b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/publicfile.go
index d4411c741d..aab421a23b 100644
--- a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/publicfile.go
+++ b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/publicfile.go
@@ -147,7 +147,7 @@ func (s *svc) handlePropfindOnToken(w http.ResponseWriter, r *http.Request, ns s
 	prefer := net.ParsePrefer(r.Header.Get("prefer"))
 	returnMinimal := prefer[net.HeaderPreferReturn] == "minimal"
 
-	propRes, err := propfind.MultistatusResponse(ctx, &pf, infos, s.c.PublicURL, ns, nil, returnMinimal, nil)
+	propRes, err := propfind.MultistatusResponse(ctx, &pf, infos, s.c.PublicURL, ns, nil, returnMinimal, nil, s.previewMimeTypes)
 	if err != nil {
 		sublog.Error().Err(err).Msg("error formatting propfind")
 		w.WriteHeader(http.StatusInternalServerError)
diff --git a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/versions.go b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/versions.go
index a621957f82..0adcc1b411 100644
--- a/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/versions.go
+++ b/vendor/github.com/opencloud-eu/reva/v2/internal/http/services/owncloud/ocdav/versions.go
@@ -200,7 +200,7 @@ func (h *VersionsHandler) doListVersions(w http.ResponseWriter, r *http.Request,
 	prefer := net.ParsePrefer(r.Header.Get("prefer"))
 	returnMinimal := prefer[net.HeaderPreferReturn] == "minimal"
 
-	propRes, err := propfind.MultistatusResponse(ctx, &pf, infos, s.c.PublicURL, "", nil, returnMinimal, nil)
+	propRes, err := propfind.MultistatusResponse(ctx, &pf, infos, s.c.PublicURL, "", nil, returnMinimal, nil, s.previewMimeTypes)
 	if err != nil {
 		sublog.Error().Err(err).Msg("error formatting propfind")
 		w.WriteHeader(http.StatusInternalServerError)