Update app.py

app.py

@@ -375,6 +375,8 @@ def update_denoise_checkboxes(images_state: List[Image.Image], task_type: str, a
 
         return gr.update(choices=labels, value=values)
     else:
+        if images_state is None:
+            images_state = []
         labels = ["image_0"] + [f"image_{i+1}" for i in range(len(images_state))]
         values = ["image_0"]
         return gr.update(choices=labels, value=values)