I don't know how much I trust this story. First of all, I've never heard of Cinemart, the site that broke these pictures. Second of all, it wouldn't be so difficult for a modestly talented fan to make a mask exactly like the one below; hell, I don't know all of the Alien merch out there, and this could just be a stripped down version of a mask that already exists.
According to Cinemart their source sent them these photos, which depict the alien from Prometheus - and which looks just like the Space Jockey from Alien. That's not a huge surprise, as we have long known that this movie was basically Space Jockey: Origins, but a human-sized version of the head is intriguing. The Space Jockey we saw in Alien was enormous, and this - if true - indicates human-sized Space Jockeys in Prometheus. Also if true: this seems to prove that the Space Jockey wasn't so much dessicated as his whole race looks like skulls, down to cracks on their heads.
What do you think? Is this legit? One other small thing that makes me wonder: these pictures have been up since last night but Fox hasn't taken them down yet. That's unusual.
UPDATE: I have talked to someone with information about the production and I am almost completely certain this is fake.