Asks fb for photo original size
        returns tuple with width,height

def _getphoto_originalsize(self,pid):
        """Asks fb for photo original size
        returns tuple with width,height
        """
        logger.debug('%s - Getting original size from fb'%(pid))
        i=self.fb.get_object(pid)
        width=i['images'][0]['width']
        height=i['images'][0]['height']
        return (width,height)