Upscaling the image by a factor of f.

def upscale(inputs, f, method=tf.image.ResizeMethod.NEAREST_NEIGHBOR):
  """Upscaling the image by a factor of f."""
  height, width = shape_list(inputs)[1:3]  # pylint: disable=unbalanced-tuple-unpacking
  return tf.image.resize_images(inputs, (height * f, width * f), method)