read image info button fix

app.py

@@ -193,9 +193,9 @@ def util_ui():
                 image = gr.Image(label="上传图片", sources=["upload"], interactive=True, type="pil")
             with gr.Column(variant='panel'):
                 info = gr.HTML('')
-                items = gr.JSON(value=None, visible=False)
+                items = gr.JSON(value={}, visible=False)
                 png2main = gr.Button('参数发送到文生图', visible=False)
-                items.change(lambda i: gr.Button(visible=False) if i is None else gr.Button(visible=True), inputs=items, outputs=png2main)
+                items.change(lambda i: gr.Button(visible=True) if len(i) else gr.Button(visible=False), inputs=items, outputs=png2main)
     return png2main, items, info, image
     
 def load_javascript():