I would doubt photoshop, you would have to be a master of photoshop to make it look that good. Once you work with photoshop long enough there are a few key things that you can look at that might tell you if a picture is a fake and this one doesn't have any of those.
People who fish for food, and sport be damned, are called pot-fishermen. The more expert ones are called crack pot-fishermen. All other fishermen are called crackpot fishermen. This is confusing. ~ Ed Zern, 1947