No, that's not a picture of a double sunset on Mars

So Curiosity's been on the Martian surface for a week, and we're already seeing faked images touted as being real. The other day it was a more-or-less honest mistake of people spreading around a computer-generated view from Mars - originally meant just to show what the skyline looked like from there - thinking it was real. Now though, we have what's clearly an actual fake. Here's the shot, getting passed around on various Tumblrs: