SEO for pictures?

We have some image rankings identical with serp rankings, and have seen a lot of difference between the two in several different ways.

#1: we get on average almost 4x as much traffic from the regular serps and from the image search.
#2: the traffic from image search does not convert nearly as well as from regular serps.

Hope this helps.

You can use the "alt" option in the <img> tag to give your picture alternate text. SE spiders make use of this text to determine images' value to your site.

Ranking images is very underestimated. Great traffic can be gained for ranking with your images.