Update app.py

app.py

@@ -98,7 +98,7 @@ with gr.Blocks() as demo:
     change_api_key.click(fn=enable_api_box, outputs=[enable_box])
 
     # Event handler for uploading a PDF
-    btn.upload(fn=render_first, inputs=[btn], outputs=[show_img])
+    pdf_upload.upload(fn=render_first, inputs=[pdf_upload], outputs=[show_img])
 
     # Event handler for submitting text and generating response
     submit_btn.click(