One one of my sites themed around web design (geared towards markup - NOT graphics), I have Googlers coming from image searches on a picture of a dog I have. The image is mere eye candy on the site, but with the help of the image's alt text, I get those visitors coming in. Not really relevant traffic, but a great "experiment" non the less. On Google's Webmaster tools, you have an option to "enhance" your site's images for search. I really suggest you do so, as you'll like the visits you get. Has anyone else noticed traffic from images?