diff --git a/src/github.com/matrix-org/dendrite/mediaapi/routing/download.go b/src/github.com/matrix-org/dendrite/mediaapi/routing/download.go
index 4a1516e1f..38c436367 100644
--- a/src/github.com/matrix-org/dendrite/mediaapi/routing/download.go
+++ b/src/github.com/matrix-org/dendrite/mediaapi/routing/download.go
@@ -305,6 +305,10 @@ func (r *downloadRequest) respondFromLocalFile(
 		}).Info("Responding with file")
 		responseFile = file
 		responseMetadata = r.MediaMetadata
+
+		if len(responseMetadata.UploadName) > 0 {
+			w.Header().Set("Content-Disposition", fmt.Sprintf(`inline; filename*=utf-8"%s"`, responseMetadata.UploadName))
+		}
 	}
 
 	w.Header().Set("Content-Type", string(responseMetadata.ContentType))
@@ -316,10 +320,6 @@ func (r *downloadRequest) respondFromLocalFile(
 		" object-src 'self';"
 	w.Header().Set("Content-Security-Policy", contentSecurityPolicy)
 
-	if len(responseMetadata.UploadName) > 0 && !r.IsThumbnailRequest {
-		w.Header().Set("Content-Disposition", fmt.Sprintf(`inline; filename*=utf-8"%s"`, responseMetadata.UploadName))
-	}
-
 	if _, err := io.Copy(w, responseFile); err != nil {
 		return nil, errors.Wrap(err, "failed to copy from cache")
 	}