var banner = new Array();

banner[0]='http://i84.servimg.com/u/f84/09/04/06/38/ryzom15.jpg';
banner[1]='http://i84.servimg.com/u/f84/09/04/06/38/lotro-15.jpg';
banner[2]='http://i84.servimg.com/u/f84/09/04/06/38/lotro17.jpg';

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

setInterval("document.getElementById('i_logo').src= banner[Math.floor(Math.random()*banner.length)];",3000);