var banner = new Array();

    banner[0]='https://i756.photobucket.com/albums/xx201/MikoYumi16/t9axi.png';
banner[1]='https://i756.photobucket.com/albums/xx201/MikoYumi16/K8W7v.png';
banner[2]='https://i756.photobucket.com/albums/xx201/MikoYumi16/EVcHr.png';


    document.getElementById('logo').firstChild.src= banner[Math.floor(Math.random()*banner.length)];