Update app.py

app.py

@@ -498,7 +498,7 @@ def reset_mask(d):
     backup = cv2.imread(backups[frame_selected]).astype(np.uint8)
     cv2.imwrite(frames[frame_selected], backup)
 
-    d["layers"][0] = None
+    d["layers"][0][0:d["layers"][0].shape[0], 0:d["layers"][0].shape[1]] = (0,0,0,0)
 
     return gr.ImageEditor(value=d)