From what I'm told (and from what I remember of what I'm told) it say something along the lines of
"Do you know who this is? He's our new ALT who will be teaching here for 1 year. His name is Jonathan Kramer. Can you say hello in English?"
The picture was taken by one of the teachers I met at the board of education meeting when I first arrived (amazing guy, even more amazing teacher) and the school as a whole is great. The posting creeped me out a little bit when I first saw it, but once I found out what it meant it made me feel even more welcome at the school.