It's out of character for Cirno to call herself a baka. For her to do that, she must have hit rock bottom. That hurts.
4717 said: It's probably some kind of diversion. It has to be.
Or it could just be that it's drawn by Yoruny. Where the joke doesn't even have to make sense or fit the character, for as long as it references something popular, people will eat it up and repost it.
Is it funny now? There is a video too (in the case you didn't find it funny because you didn't knew the reference).
The very fact that the pic needs to be explained for anyone to find it humorous, and even then it still just doesn't fit... speaks a lot about the large bulk of this "artist"'s "works" as a whole. How anyone can even say "in the case you didn't find it funny because you didn't knew the reference" with a completely straight face without cringing themselves to dead, is beyond me