window.onload = choosePic;

var myPix = new
Array("images/front_images/01.png", "images/front_images/02.jpg", "images/front_images/03.jpg", "images/front_images/04.jpg");

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