Recently I've found an interesting site <a href="http://www.pskiller.com/" rel="nofollow">Photoshopped Image Killer</a> that can detect fake images. Most image analysis software will be created to recognise shapes and objects. But this software is something which can trace manipulations. It's not much more complex than recognising objects, but almost no one is interested in this kind of software except of course to detect if an image is real or fake...