Fix bug

src/prediction.py

@@ -1,7 +1,9 @@
 import os
 import re
-from glob import glob
 import cv2
+import numpy as np
+from glob import glob
+
 from src.cyano import Cyanotype
 from src.mono_alternative import MonoAlternative
 
@@ -65,4 +67,4 @@ def optimize_img(process_name, img):
   out_path = f'{out_dir}/x0_{suf}.png'
   cv2.imwrite(out_path, x0)
 
-  return x0, opt_img
+  return x0.astype(np.uint8), opt_img.astype(np.uint8)