I've implemented CDN for Joomla Pro in
www.3dastudio.com
and linked to SimpleCDN. But little or nothing is being delivered by the CDN. This may be to do with a lot of the images being delivered by Ajax.
CDN for Joomla can only change the urls for images that are in your html output. It does not control images loaded through javascript (if those paths are not in the html output).
It also does handle dynamic images, like the images on your site. Those images are created via a com_ajax url, and are not actually image paths.