var banner = new Array();

banner[0]='https://nsm03.casimages.com/img/2010/04/27/100427120720532125914352.png';
banner[1]='https://nsm03.casimages.com/img/2010/04/26/100426113509532125914183.png';
banner[2]='https://nsm03.casimages.com/img/2010/04/27/100427030538532125914700.png';

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