Google image search has always been a great tool for finding images of things, but it has never been great for really dialing down what you want based on the image composition. They’ve recently added the ability to dial down your search by image type, which is great for finding specific things that you want. For instance: I can search for line drawings of vermont. Interestingly that search brings up a lot of maps. Maybe in the future, they will add “maps” as a criteria.
Comparison
Google image search still isn’t as robust as something like iStockPhoto, but I think that is probably the culprit of some sort of technical difference in their systems (i.e. Google is indexing images and iStockPhoto is all user submitted images). Because iStockPhoto has user submitted entries, they can enter meta data that Google just can’t derive from just the image.
Capabilities
Right now, you can filter image searches by news content, faces, clip art, line drawings, and photo content. They are using photo recognition and search data to add additional meta data to the images. For instance, the news content option checks the surrounding text around the images for meta data that pertains to news. They can use photo recognition algorithms for recognizing facial structures in the images.
The Future?
I’m hoping maybe someday they will add features similar to iStockPhoto like color recognition and content layout. Color layout is something that I’ve been looking forward to for a while now. It’d make it really easy to pick up images that go with a specific theme in a website design or something to that effect.