I have been working on a couple of sites and was curious to see the new “best practices” for image titles and “alt” tags. Going through Google recommendations I came across this posting of Peter Linsley from Google, which helped to answer my question. He says “The filename can give Google clues about the subject matter of the image. Try to make your filename a good description of the subject matter of the image. For example, my-new-black-kitten.jpg is a lot more informative than IMG00023.JPG. Descriptive filenames can also be useful to users: If we’re unable to find suitable text in the page on which we found the image, we’ll use the filename as the image’s snippet in our search results.”
