var banner = new Array();

banner.push('http://i61.servimg.com/u/f61/12/51/88/62/lagion10.jpg');
banner.push('http://i61.servimg.com/u/f61/12/51/88/62/logo111.jpg');
banner.push('http://i61.servimg.com/u/f61/12/51/88/62/img_4410.jpg');

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