Make photo library offline-first and fix video thumbnails

Server/services/thumbnails/pkg/preprocessor/preprocessor_test.go

@@ -173,6 +173,13 @@ var _ = Describe("ImageDecoder", func() {
 			Expect(decoder).To(BeAssignableToTypeOf(GifDecoder{}))
 		})
 
+		It("should return a VideoDecoder for supported video types", func() {
+			for _, mimeType := range []string{"video/mp4", "video/quicktime", "video/webm", "video/x-matroska"} {
+				decoder := ForType(mimeType, nil)
+				Expect(decoder).To(BeAssignableToTypeOf(VideoDecoder{}))
+			}
+		})
+
 		It("should return an GgsDecoder for ggs types", func() {
 			decoder := ForType("application/vnd.geogebra.ggs", nil)
 			// This will not return the expected ggsDecoder, but an ImageDecoder since ggs contains an embedded png.