Google today announced the Image indexing improvements.
"We're constantly working to improve our crawling and indexing systems to help people find the most recent information on the web, whether it's a blog, a video or an image. The biggest change this year was Caffeine, which made search results 50% fresher on average. More recently, we made some changes to increase the rate at which we update images in our index. These improvements will help people find fresher images in both web and image search," said Google.