We are running oscommerce, and we currently have a mod installed that allows us to add multiple images for the thumbnail.
So when there are 2 + images it displays the main thumbnail then the addittional ones below it in a smaller format.
I would ours to work just like these guys thumbnail:
[url removed, login to view]
If you scroll over on of the thumbnails, it replaces the current one etc...
We want ours to exactly like this including the way the pop up works.
Please let me know if you need furthe explanation.