diff --git a/cgi-bin/paint_x2_unet/img2imgDataset.py b/cgi-bin/paint_x2_unet/img2imgDataset.py
index 86d0247..3d424a7 100755
--- a/cgi-bin/paint_x2_unet/img2imgDataset.py
+++ b/cgi-bin/paint_x2_unet/img2imgDataset.py
@@ -21,6 +21,23 @@ def cvt2YUV(img):
         img = cv2.cvtColor( img, cv2.COLOR_BGR2YUV )
     return img
 
+def cvt2GRAY(img):
+    if len(img.shape) == 2:
+        # Grayscale image
+        return img
+    width, height, color = img.shape
+    if color == 4:
+        # RGBA image
+        r, g, b, a = cv2.split(img)
+        white = (255 - a).repeat(3).reshape((width, height, 3))
+        img2 = cv2.merge((r, g, b)).astype(np.uint32)
+        img2 += white
+        img2 = img2.clip(0, 255).astype(np.uint8)
+        return cv2.cvtColor(img2, cv2.COLOR_RGB2GRAY)
+    else:
+        # RGB image
+        return cv2.cvtColor(img, cv2.COLOR_RGB2GRAY)
+
 class ImageAndRefDataset(chainer.dataset.DatasetMixin):
 
     def __init__(self, paths, root1='./input', root2='./ref', dtype=np.float32):
@@ -39,7 +56,10 @@ def get_example(self, i, minimize=False, blur=0, s_size=128):
         path1 = os.path.join(self._root1, self._paths[i])
         #image1 = ImageDataset._read_image_as_array(path1, self._dtype)
 
-        image1 = cv2.imread(path1, cv2.IMREAD_GRAYSCALE)
+        #image1 = cv2.imread(path1, cv2.IMREAD_GRAYSCALE)
+        image1 = cv2.imread(path1, cv2.IMREAD_UNCHANGED )
+        image1 = cvt2GRAY(image1)
+        
         print("load:" + path1, os.path.isfile(path1), image1 is None)
         image1 = np.asarray(image1, self._dtype)