Hi threelefts,
Yeah this is a pretty cool way of showing images its called lightbox. There are a few variations on the web to make it smaller in file size and a few extra capabilities but the original that I use can be found at
http://www.huddletogether.com/projects/lightbox2/.
You should b able to apply this to your site pretty easy buy the examples they show or by just looking at my source code.
Regards Andy
http://www.griffinwebdesign.co.uk/