A WebmasterWorld thread has users noticing changes over at Google Image Search. The changes may be a filter or may be a full-blown image index update, hard to tell at the moment.
The last Google Image update seemed to be an image filter update in September. But now, the update seems a bit more outside of the scope of what we would classify as a filter.
WebmasterWorld administrator, tedster, observed:
Senior member, zeus, who reported the image update has seen tons of images drop out of Google Image search, plus he has seen a possible hotlink image bug. The hotlink image bug happens when a third-party site links to a specific image and Google classifies that image from a a third-party domain.
Forum discussion at WebmasterWorld .