var banner = new Array();

banner[0]='http://i53.tinypic.com/2hqbdro.png';
banner[1]='https://img10.hostingpics.net/pics/154506b2.png';
banner[2]='https://i.servimg.com/u/f72/15/92/27/19/uc110.jpg';

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