Checks if image file (fn) with photo_id (pid) has already
        been resized on fb. If so, returns True

def _already_resized_on_fb(self,fn,pid,_megapixels):
        """Checks if image file (fn) with photo_id (pid) has already
        been resized on fb. If so, returns True"""
        logger.debug("%s - resize requested"%(fn))
        # Get width/height from fb
        width_fb,height_fb=self._getphoto_originalsize(pid)
        # Now compute what image will be if we resize it
        new_width,new_height=pusher_utils.resize_compute_width_height(\
                fn,_megapixels)
        logger.debug("%s - fb %d/%d, current %d/%d"\
                %(fn,width_fb,height_fb,new_width,new_height))
        # Check both cases since FB sometimes rotates photos
        if width_fb==new_width and height_fb==new_height:
            return True
        elif width_fb==new_height and height_fb==new_width:
            return True

        return False