var banner = new Array();

banner[0]='https://lh4.googleusercontent.com/-SYahL7_osZE/T0rpN5PSIOI/AAAAAAAAB5A/qABLOKSwK2s/s1055/Header%2520Basev2.png';

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