var banner = new Array();

banner[0]='https://i.servimg.com/u/f39/17/39/81/06/sg10.jpg';
banner[1]='https://i.servimg.com/u/f39/17/39/81/06/sg210.jpg';
banner[2]='https://i.servimg.com/u/f39/17/39/81/06/sg310.jpg';
banner[3]='https://i.servimg.com/u/f39/17/39/81/06/sg410.jpg';
banner[4]='https://i.servimg.com/u/f39/17/39/81/06/logoge10.jpg';

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