Nope. Try again. I knew about this image long before threads like these started popping up. My opinion has remained the same since it's release. Want evidence? The textures make it look like it's from Borderlands or Rage even. How do you explain that? Things are set up too perfectly such as the sunset in the background and the mist along the rocks. It is obviously artwork or an edited screenshot.
Right... did you ever stop to think that this may have been designed to be a poster? It's certainly shaped like one.
As for being in game like Pete Hines supposedly said, cutscene anybody?
You are absolutely right, something doesnt look quite right about it to be in game. But I still think it simply looks a bit strange because it is SO much detail all in one screenshot. Which would make sense, if it were multiple screens linked together.
Your right though and it could be a cutscene, or even a behind the scenes 'far in the distance' view of areas that arent actually in game. That would also make sense as to why it looks so spectacular. I remember Halo (all of them) had some downright amazing 'out of map' views of areas you couldnt get to.
But even if it was a cutscene chances are it would still be an in the game location. It might not necessarily look like that, but Im sure a cutscene of Skyrim would contain actual places in game. Id hope so anyways.
I guess only time will tell for sure.