Interesting read on how changes in a jpeg image through Photoshop can be tracked through forensic analysis:
How the 2013 World Press Photo of the Year was faked with Photoshop
When is an image fake, and when is it merely enhanced?
The bigger discussion, of course, is whether Gaza Burial is actually fake — or just enhanced to bring out important details. This is a question that has plagued photography since its inception. Should a photo, especially a press photo, be purely objective? Most people think the answer is an obvious “yes,” but it’s not quite that simple. What if a photo is perfect, except that it’s taken at an odd angle — can you digitally rotate it? What about cropping? What if there’s dust on the lens/sensor/film — can you digitally remove it?Perhaps most importantly, though, cameras simply don’t capture the same gamut of color or dynamic range as human eyes — a photo never looks the same as the original image perceived by your brain. Is it okay for a photographer to modify a picture so that it looks exactly how he remembers the scene?