fix: Update Gradio UI layout for image generation and processing

app.py

@@ -273,7 +273,11 @@ with gr.Blocks() as demo:
     mv_images = gr.State()
 
     submit_prompt.click(fn=generate_image, inputs=[prompt], outputs=input_image).success(
-        fn=preprocess, inputs=[input_image, True], outputs=[processed_image]
+        fn=preprocess, inputs=[input_image, do_remove_background], outputs=[processed_image]
+    )
+    submit_process.click(fn=check_input_image, inputs=[input_image]).success(
+        fn=preprocess, inputs=[input_image,
+                               do_remove_background], outputs=[processed_image],
     )
     submit_mesh.click(fn=generate_mvs, inputs=[processed_image, sample_steps, sample_seed], outputs=[mv_images, mv_show_images]).success(
         fn=make3d, inputs=[mv_images], outputs=[