Hmmm, could be. Personally I think it looks CGI, however probably closer to NextGen quality. Remember when Oblivion came out how it totally shocked everyone with its graphics, it might be the same thing. Although, I guess there's no substantial proof, so we'll have to wait and see.
sorry I'm flaking out on this source
I swear to god there was a thread full of concrete evidence and convincing arguments that it's fake
but, also, keep in mind that skyrim and oblivion will be running on the same machine, so skyrim's graphics can't simply be upgraded, they can only be optimized. You won't see any drastic difference between the games, like that picture would lead on.
As well as the fact that even the NAME of the game was kept secret until the VGAs. A leaked screenshot would be pretty astounding considering we weren't even sure what it was called.