^ If it is Photoshopped, it was done by a professional who knew what they were doing. All the shadows around his junk look like natural lighting effects that happened when the photo was actually shot, as opposed to mechanical reproductions via computer - photoshopping.
A good general rule of thumb is this - if you want to tell whether a picture of a naked man has been 'shopped to make his dick larger, the best way to tell is to take a good, hard (pun very much intended

) look at the shadows immediately surrounding his dick and balls. If those shadows look either heavily pixellated and/or darker than a normal shadow of that area would look like, then yes, the picture has been photoshopped and altered.
This is real. You'll note the shadow on his left inner-thigh.
So is this one. Look at the shadows around his balls - yes, they're darker, stronger shadows. But the overall pic was taken in darker lighting, in a professional photoshoot setting.
This picture of porn star Topher DiMaggio is also real. I believe this was taken for
Men.com
^ I can't find it quickly, in order to include it in this post, but yes, there is a fake copy of this exact picture of Topher DiMaggio. They actually kept the body, underwear, dick, and I think the tattoo on his lower abs, too. But they photoshopped somebody else's face over Topher's - a mid-30s Hispanic man, with black hair and beard stubble. He was cute, but having seen this pic before, and knowing that it was TDM's pic, I knew that that one was indeed fake.