I'm seeing this exact method being used on cgtalk.com and I could really use something like this on my site. However I don't know how to code it. You can see it in action here:
http://www.cgtalk.com/forumdisplay.php?f=121
It auto formats the thumbnails to a specific size by adding black. Very cool. If anyone knows how to do this it would be a great tool for alot of site's that are about photos, graphics, or images.. etc.
Aceman