code: def image(self, size):
          
          assert(size[0])
          assert(size[1])
          return self._image.crop(box=self._crop_box(size))
docs: :param size: The width, height of the image composition.
          :type size: tuple
          :returns: An image, cropped to the boundaries specified
              by ``size``.
          :rtype: PIL.Image.Image