If I was a lawyer, I would argue that the art is different enough from the photograph, in that it uses a completely different technique and another composition. Any person who was at the New Yersey Renaissance fair could have drawn that guy without ever knowing that picture. Sure, the pose is the same, but again, as a hypothetical lawyer, is it unique enough to be protected by copyright? I'd say no. You can use a pose as an argument on a world famous picture like Michelangelo's divine spark in the sistine chapel, but hardly for a picture of just two regular people, which don't even appear together in the copied picture.
About the outfit, sure, but again, is it unique enough?
It's not like I disagree that this was wrong. I just think that as an artist, taking a real world model to base your art on isn't exactly a felony. Sure, he SHOULD have altered the costume, and also tweaked the pose, but I can't quite share the same level of contempt that RGG replied with. It's not like he stole somebody else's drawing. I guess he implicitly passed the costume design as his own, so I can see why you'd be mad about that.