I don't know the deal with these shots but there was already one issue with Mass Effect screenshots, someone released shots that weren't fully optimized or not fully rendered in-game yet, meaning they simply didn't look as good as it would in the actual product. I don't know if this is the same situation, but I can tell you these shots are not on Bioware's website, a site that has plenty of shots, for example this:(and this shot was posted May 10th so it is a recent depiction of the game):
There is also plenty of ingame video footage of how good this game looks, it's insane, it looks amazing. And anyone who doubts that, just try Jade Empire which may very well be the best looking x-box game out there. Bioware is capable of many things and this game with novel already out(I'm currently reading it), promised extra missions for and a triliogy planned you can safely say this is the beloved baby. It won't be anything short of amazing.
Go to: http://www.masseffect.bioware.com