I can probably count on one hand the number of times I've blogged about a forum thread, but this thread on image optimization from Cre8asite forums is one to read. Let's face it, there's not a lot said about image optimization, so any time I find information like this, I do a little seo dance. Here are just a few snippets from the thread to entice you to read further.
Regarding a Microsoft patent:
Basically there is an image relevance scoring system, i.e. algo input and/or filter (details follow)
And a text-image relevance scoring system (details follow)
And then Yannis chimes in with some observations from testing:
Enclose your images always in divs...
Display images any images that you want the search engines to know about at the beginning of the page...
Give your images a title with a heading in...
...and so much more...
I may take some of these ideas and run some tests of my own, but in any case, this is all very interesting stuff. Check it out when you get a chance.