Yeah, that's the same thing I saw. The image of Luna in a hood is fantastic, I love it I'll bet she's grinning maniacally because she's hatching a plan or something, or maybe going to pull a lighthearted prank on Ponyville or something. I doubt she's going to be an antagonist, which is a speculation I have heard others say.
Edit: Assuming, of course, that it's real. I really hope it is, though.