Can Atahualpa do this? Define the image for Facebook links?

I found this guide intriguing, but it's intended for Thesis:

http://www.wolf-howl.com/blogs/thesis-digg-facebook/

Is there a way to do this with Atahualpa? It's basically a way to tell Facebook and Digg what image to use when you post a link from your site to them.

I am guessing you would have use a custom field with the URL of the image you want, but I am not exactly sure how to do this using Atahualpa "language" and every time I've tried to edit the functions of Atahualpa it crashes.