Actually I think the Maxim isn't bad photoshopping at all and just the angle of the shot. And I actually remember seeing that Maxim cover exactly as depicted there on a desk at work and looking very closely at exactly that part of the image for reasons of photo curiosity (honest).
As for the others I'm not sure. Some of these are shocking examples of bad Photoshop work if true. The blogger is very convincing if it's a fake though.
Would be something of a post modern irony if this site was artifice too...