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I have a color photo. Is it possible to find out whether it is original or made by photo-shop?

marked as duplicate by Imre, Matt Grum, Philip Kendall, mattdm, Esa Paulasto Mar 21 '14 at 10:47

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This page explains Error Level Analysis (ELA), which can be used on JPEG images to tell from error levels whether an image has been digitally modified. It's not a precise art, though.

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