var myPix = new Array("Images/Urban_Design1.jpg","Images/Urban_Design2.jpg","Images/Urban_Design3.jpg","Images/Urban_Design4.jpg","Images/Urban_Design5.jpg");

function choosePic() {
	randomNum = Math.floor((Math.random() * myPix.length));
	document.getElementById("random_background").src = myPix[randomNum];
}