var theImages = new Array() 
theImages[0] = 'images/cover01.jpg'
theImages[1] = 'images/cover02.jpg'
theImages[2] = 'images/cover03.jpg';
var whichImage = Math.round(Math.random()*((theImages.length)-1));
function showImage(){document.write('<img src="'+theImages[whichImage]+'">');}