reverted images to unsigned bytes

SPIDER.py

@@ -55,8 +55,8 @@ def standardize_3D_image(
         image = np.transpose(image, axes=[1, 2, 0])
     # Resize image
     image = skimage.transform.resize(image, resize_shape)
-    # # Rescale to UInt8 type
-    # image = skimage.img_as_ubyte(image)
+    # Rescale to UInt8 type (required for PyArrow and PIL)
+    image = skimage.img_as_ubyte(image)
     return image