There are some early reports at WebmasterWorld of ranking changes and indexing changes within Google Image search.
The reports say that around November 15th and 16th some webmasters noticed a change in search traffic via Google Image search.
One webmaster said:
This webmaster blames the new top navigation whereas another webmaster blames Google’s indexing of images. He wrote:
The last time we saw reports of a Google Image update was on October 1st.
Image updates are hard to spot since many webmaster do not track the results and traffic from image search.
Forum discussion at WebmasterWorld.