Google seems to be testing a brand new design for image search. I personally do not see it, but as I reported at the Search Engine Roundtable a few days ago, some people are seeing the new image search design.
Today, I finally found pictures of the design via a Twitter user. Here is the new Google Image Search design that Google appears to be testing:
Supposedly, the images continue to scroll in as you scroll through the page. This is very different from the current live image search design.