Generate preview regardless of HasPreviewImage value (#16535)

Automatic Merge

api4/file_test.go

@@ -404,6 +404,18 @@ func TestUploadFiles(t *testing.T) {
 			expectedImageHasPreview:     []bool{true},
 			expectedCreatorId:           th.BasicUser.Id,
 		},
+		// animated GIF
+		{
+			title:                       "Happy image thumbnail/preview 12",
+			names:                       []string{"testgif.gif"},
+			expectedImageThumbnailNames: []string{"testgif_expected_thumbnail.jpg"},
+			expectedImagePreviewNames:   []string{"testgif_expected_preview.jpg"},
+			expectImage:                 true,
+			expectedImageWidths:         []int{118},
+			expectedImageHeights:        []int{118},
+			expectedImageHasPreview:     []bool{false},
+			expectedCreatorId:           th.BasicUser.Id,
+		},
 		{
 			title:                    "Happy admin",
 			client:                   th.SystemAdminClient,

app/file.go

@@ -793,19 +793,19 @@ func (t *UploadFileTask) postprocessImage(file io.Reader) {
 	}
 
 	var wg sync.WaitGroup
-	wg.Add(1)
-	if t.fileinfo.HasPreviewImage {
-		wg.Add(2)
-		go func() {
-			defer wg.Done()
-			writeJPEG(genThumbnail(decoded), t.fileinfo.ThumbnailPath)
-		}()
+	wg.Add(3)
+	// Generating thumbnail and preview regardless of HasPreviewImage value.
+	// This is needed on mobile in case of animated GIFs.
+	go func() {
+		defer wg.Done()
+		writeJPEG(genThumbnail(decoded), t.fileinfo.ThumbnailPath)
+	}()
+
+	go func() {
+		defer wg.Done()
+		writeJPEG(genPreview(decoded), t.fileinfo.PreviewPath)
+	}()
 
-		go func() {
-			defer wg.Done()
-			writeJPEG(genPreview(decoded), t.fileinfo.PreviewPath)
-		}()
-	}
 	go func() {
 		defer wg.Done()
 		if t.fileinfo.MiniPreview == nil {