function getRandomImage() {
	if (typeof(urls) == 'undefined'){
		urls = new Array('/img/home-image-1.jpg','/img/home-image-2.jpg','/img/home-image-3.jpg');
		imgs = new Array(urls.length);
	}
	if (document.images) {
		for (var i=0; i<imgs.length; i++) {
			var img = new Image();
			img.src = urls[i];
			imgs[i] = img;
		}
	}
	var rn = Math.floor(Math.random()*imgs.length);
	if (imgs[rn]) {
		document.getElementById("homeImage").style.backgroundImage = "url(" + imgs[rn].src + ")";
	}
}

addEvent(window, 'load', getRandomImage);