Photo Finder

[waregim]

I have a large collection of jpgs that I want to sort, roughly by category. I am looking for software that can detect skin tones, and sort to 'People', greens and blues and sort to 'nature', greys and silver and sort to 'cityscape' - that type of thing.

Does it exist? And where?

Also I am looking for a recommended photo de-duplicator, able to detect similar photos of different sizes.
I had a pretty decent one from firmtools, but it de-registered, and is no longer on the net.