var banner = new Array();

banner.push('https://i.servimg.com/u/f43/14/73/24/79/x3_bmp10.jpg');
banner.push('https://i.servimg.com/u/f43/14/73/24/79/x1_bmp10.jpg');
banner.push('https://i.servimg.com/u/f43/14/73/24/79/x2_bmp10.jpg');
banner.push('https://i.servimg.com/u/f43/14/73/24/79/x4_bmp10.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)];",60000);