var banner = new Array();

banner[0]='https://i1103.photobucket.com/albums/g480/marmotalecter/maliss-1.png';
banner[1]='https://i1103.photobucket.com/albums/g480/marmotalecter/popppcopy.png';
banner[2]='https://i1103.photobucket.com/albums/g480/marmotalecter/grilss-1.png';

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