error fix

app.py

@@ -124,9 +124,9 @@ def predict(input_img, ver):
     R, G, B = 0, 1, 2
     # constant by which each pixel is divided
 
-    Red = source[R].point(lambda x: darken_pixel(x))
-    Green = source[G].point(lambda x: darken_pixel(x))
-    Blue = source[B].point(lambda x: darken_pixel(x))
+    Red = source[R].point(lambda i: i / 2.0)
+    Green = source[G].point(lambda i: i / 2.0)
+    Blue = source[B].point(lambda i: i / 2.0)
 
     im_output = Image.merge(im_output.mode, (Red, Green, Blue))
     return im_output