var banner = new Array();

banner.push('http://www.ohmydollz.com/img/avatar/2113160.png');
banner.push('http://www.ohmydollz.com/img/avatar/4417186.png');
banner.push('http://www.ohmydollz.com/img/avatar/4257335.png');
banner.push('http://img696.imageshack.us/img696/2134/sanstitre5ji.png');

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);