var banner = new Array();
    banner.push('http://hitskin.com/themes/16/92/03/i_logo.jpg');
    banner.push('https://i.servimg.com/u/f20/11/38/94/07/halo_r10.jpg');
    banner.push('https://i.servimg.com/u/f62/15/92/63/11/test212.jpg');
    banner.push('https://i.servimg.com/u/f42/14/32/80/26/logo10.jpg');

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