Sometimes, sure. Law.com published a useful article on "Detecting Photoshop Fraud" last week. Unfortunately, it's much more than Photoshop we have to deal with. There are tons of programs that will alter photos and they require little to no sophistication on the part of the user.
Happily, most photo alteration is so clumsily done that there are often visual clues:
- The lighting is wrong
- Orphan shadows and reflections
- Varying levels of color density and hue
- Blurred edges on objects and figures
If the fakes are good, you're going to have to examine the photo at the pixel level and look for things like anti-aliasing (the way graphics programs smooth jagged edges in images by averaging the colors of the pixels at the edge). Unless the person is fairly competent, the edges will look rough.
There are also the sometimes hilarious "baroque anatomies" with large heads on small bodies, extra appendages - often comically unintended freak shows. If Photoshop disasters amuse you, feel free to waste a little time at the website Photoshop Disasters. This is why I hire experts. I know I could create a disaster without half trying.
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