window.onload = function () {
var header = document.getElementById('FlashPane');
var pictures = new Array();
pictures[0] = 'http://www.autocadexchange.com/Portals/2/Skins/UmbrellaPortal/images/Headers/header01.jpg';
pictures[1] = 'http://www.autocadexchange.com/Portals/2/Skins/UmbrellaPortal/images/Headers/header02.jpg';
pictures[2] = 'http://www.autocadexchange.com/Portals/2/Skins/UmbrellaPortal/images/Headers/header03.jpg';
pictures[3] = 'http://www.autocadexchange.com/Portals/2/Skins/UmbrellaPortal/images/Headers/header04.jpg';

var numPics = pictures.length;

if (document.images) {
	var chosenPic = Math.floor((Math.random() * numPics));
	header.style.background = 'url(' + pictures[chosenPic] + ')';
	header.style.backgroundRepeat = "no-repeat";
	}
	
}