Update app.py

app.py

@@ -177,7 +177,7 @@ load_js = """
         var vv = document.getElementById("txt_box");
         vv.innerHTML=a;
         var ii = document.getElementById("im_up");
-        ii.innerHTML['src']=a;
+        ii.src=a;
         }
     """  
 link_js="""