Popup window - Zoom image including different color of the same product (thumbnail)

Hi,
I've built an online catalog, here's the link:
http://opticasetinc.com/webv1/toxic_acetate.php

If you click on any product ref, you'll see a popup window including the properties of the item and a bigger picture.

What I would like to do is to add on the same popup different colors of that same item (like thumbnails) and if you click on different thumbnail (colors) , the current pic will change to another color.
Please is there any tutorial to explain me that? Please let me know.

Thank you.