var banner = new Array();

banner[0]='https://i.imgur.com/UxzuI8T.png';
banner[1]='https://i.imgur.com/d8PLKfb.png';
banner[2]='https://i.imgur.com/pSUlR5X.png';
banner[3]='https://i.imgur.com/QOoMdX5.png';
banner[4]='https://i.imgur.com/agrQ2pY.png';
banner[5]='https://i.imgur.com/115UqsC.png';
banner[6]='https://i.imgur.com/VMSruWH.png';
banner[7]='https://i.imgur.com/klKy8L1.png';

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