diff --git a/changelog/unreleased/preview-api.md b/changelog/unreleased/preview-api.md
new file mode 100644
index 0000000000..1da2b5c50d
--- /dev/null
+++ b/changelog/unreleased/preview-api.md
@@ -0,0 +1,5 @@
+Enhancement: implement preview API
+
+Added the API endpoint for file previews.
+
+https://github.com/owncloud/ocis-webdav/pull/13
diff --git a/pkg/dav/thumbnails/thumbnail.go b/pkg/dav/thumbnails/thumbnail.go
index 6e6646ef4f..e8ba4b1348 100644
--- a/pkg/dav/thumbnails/thumbnail.go
+++ b/pkg/dav/thumbnails/thumbnail.go
@@ -11,8 +11,10 @@ import (
 )
 
 const (
-	// DefaultSize defines the default width and height of a thumbnail
-	DefaultSize = 32
+	// DefaultWidth defines the default width of a thumbnail
+	DefaultWidth = 32
+	// DefaultHeight defines the default height of a thumbnail
+	DefaultHeight = 32
 )
 
 // Request combines all parameters provided when requesting a thumbnail
@@ -31,11 +33,11 @@ func NewRequest(r *http.Request) (Request, error) {
 	query := r.URL.Query()
 	width, err := strconv.Atoi(query.Get("x"))
 	if err != nil {
-		width = DefaultSize
+		width = DefaultWidth
 	}
 	height, err := strconv.Atoi(query.Get("y"))
 	if err != nil {
-		height = DefaultSize
+		height = DefaultHeight
 	}
 
 	etag := query.Get("c")
diff --git a/pkg/service/v0/instrument.go b/pkg/service/v0/instrument.go
index ac606a72ad..7f3bcaedc1 100644
--- a/pkg/service/v0/instrument.go
+++ b/pkg/service/v0/instrument.go
@@ -24,7 +24,7 @@ func (i instrument) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	i.next.ServeHTTP(w, r)
 }
 
-// Dummy implements the Service interface.
+// Thumbnail implements the Service interface.
 func (i instrument) Thumbnail(w http.ResponseWriter, r *http.Request) {
 	i.next.Thumbnail(w, r)
 }
diff --git a/pkg/service/v0/tracing.go b/pkg/service/v0/tracing.go
index 57ec3ec4cc..6deb60a37d 100644
--- a/pkg/service/v0/tracing.go
+++ b/pkg/service/v0/tracing.go
@@ -20,7 +20,7 @@ func (t tracing) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	t.next.ServeHTTP(w, r)
 }
 
-// Dummy implements the Service interface.
+// Thumbnail implements the Service interface.
 func (t tracing) Thumbnail(w http.ResponseWriter, r *http.Request) {
 	t.next.Thumbnail(w, r)
 }