fix update_btn

app.py

@@ -175,7 +175,7 @@ def rename_save_img(path, payload, save):
 def update_btn_cost(w, h, s, sm, dyn, i2i_img, i2i_str, inp_img, selection):
     if selection == 'i2i' and i2i_img is not None:
         cost = calculate_cost(w, h, s, False, False, i2i_str)
-    elif selection == 'inp' and inp_img is not None:
+    elif selection == 'inp' and inp_img['background'].getextrema()[3][1] > 0:
         cost = calculate_cost(w, h, s, False, False)
     else:
         cost = calculate_cost(w, h, s, sm, dyn)