var banner = new Array();

banner.push('http://img97.imageshack.us/img97/551/imageprincipalegala.jpg');
banner.push('http://img196.imageshack.us/img196/2899/imageprincipalecassie.jpg');
banner.push('http://img413.imageshack.us/img413/2300/imageprincipaleaaron.jpg');
banner.push('http://img825.imageshack.us/img825/5967/imageprincipalehelmut.jpg');
banner.push('http://img338.imageshack.us/img338/6232/imageprincipalekevin.jpg');
banner.push('http://img52.imageshack.us/img52/6873/imageprincipalekyle.jpg');
banner.push('http://img217.imageshack.us/img217/6225/imageprincipalethalia.jpg');
banner.push('http://img192.imageshack.us/img192/6957/imageprincipalecasey.jpg');
banner.push('http://img521.imageshack.us/img521/2889/imageprincipaleemily.jpg');
banner.push('http://img831.imageshack.us/img831/8312/imageprincipalelauren.jpg');
banner.push('http://img818.imageshack.us/img818/2646/imageprincipaleder.jpg');

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