diff --git a/pkg/domain/infra/abi/images.go b/pkg/domain/infra/abi/images.go
index 235f4db2a7..64695ad94b 100644
--- a/pkg/domain/infra/abi/images.go
+++ b/pkg/domain/infra/abi/images.go
@@ -56,7 +56,18 @@ func (ir *ImageEngine) Prune(ctx context.Context, opts entities.ImagePruneOption
 	}
 
 	if !opts.All {
-		pruneOptions.Filters = append(pruneOptions.Filters, "dangling=true")
+		// Issue #20469: Docker clients handle the --all flag on the
+		// client side by setting the dangling filter directly.
+		alreadySet := false
+		for _, filter := range pruneOptions.Filters {
+			if strings.HasPrefix(filter, "dangling=") {
+				alreadySet = true
+				break
+			}
+		}
+		if !alreadySet {
+			pruneOptions.Filters = append(pruneOptions.Filters, "dangling=true")
+		}
 	}
 	if opts.External {
 		pruneOptions.Filters = append(pruneOptions.Filters, "containers=external")
diff --git a/test/apiv2/10-images.at b/test/apiv2/10-images.at
index 1a3ee338d9..dba0eb3210 100644
--- a/test/apiv2/10-images.at
+++ b/test/apiv2/10-images.at
@@ -164,6 +164,8 @@ t DELETE libpod/images/test:test 200
 t GET images/json?filters='{"label":["xyz"]}' 200 length=0
 t GET libpod/images/json?filters='{"label":["xyz"]}' 200 length=0
 
+# Must not error out: #20469
+t POST images/prune?filters='{"dangling":["false"]}' 200
 
 # to be used in prune until filter tests
 podman image build -t test1:latest -<<EOF