update

app.py

@@ -126,8 +126,11 @@ def server(input: Inputs, output: Outputs, session: Session):
     @render.image
     def image():
         here = Path(__file__).parent
-        img = {"src": input.image_input()[0]['datapath'], "width": "500px"} 
-        return img if img else None
+        if input.image_input():
+            src = input.image_input()[0]['datapath']
+            img = {"src": src, "width": "500px"} 
+            return img
+        return None
 
 
 # "darkorange", "purple", "cyan4"