As an addition to the included "Image Effects" sample, here is another script that uses the Python Imaging Library (PIL) in combination with the new image-related functions in the clipboard module to create image macros.

Version 1 (faster, but results look slightly worse):
https://gist.github.com/4034426

Version 2 (quite a bit slower, but better-looking results):
https://gist.github.com/4034427