After School Virgin Album Polaroids?

I got the After School Virgin album (non autographed). It comes with a polaroid photocard (I got Nana). I have looked at various unboxings and all of the polaroids are autographed with a nice backing. But mine is a completely different photo, and it has no backing or autograph. It just looks like it has just come out of a fujifilm instax camera (it says that on the back). The picture is of Nana in her 'Lets Step it Up' costume with her hand in a 'V'. If anyone could tell me why i'd be grateful. I'm just wondering why...