A couple more questions for this topic.
How long does it take to be indexed by yahoo and google for the image search?
Does it make a difference if the image are in the root file or sub-folders?
I've scene images being listed by just having alt tags, others by just image name. So the best solution would be image name and alt tag to be the keyword?
Also does page rank matter for image search? What are the stipulations for being ranked higher in the image search?
Does file size matter? jpg vs. gif which is better?