Fix for PNG support at quarter resolution.

td01_natural-ground-textures.py

@@ -93,7 +93,7 @@ class NaturalGroundTextures(datasets.GeneratorBasedBuilder):
 
             # PNG files only available at quarter resolution.
             if self.config.name[:3] == "PNG":
-                sz = (sz*4, sz*4)
+                sz = (sz[0]*4, sz[1]*4)
 
             # Resize the images as specified by the user.
             if self.config.name[-2:] == "1K":