New answers tagged image-manipulation
Harry Farid http://www.cs.dartmouth.edu/farid/ is a professor at Dartmouth who has done a lot of work in this area and also maintains a compilation of the work of others in the field. There an quite a number of ways of detecting a manipulated image. For jpegs, the easiest way by far is to upload the image to the verification tool he has on his site :)
Photoshop's lookup tables might be the tool that you're looking for, since you can arbitrarily assign input colors to output colors using them. Another possibility is this: http://www.ximagic.com/q_index.html because you can specify a custom pallet for the output image.
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