// JavaScript Document
<!--

	var image1 = new Image();
	image1.src = "img/arriba1.gif";
	var image2 = new Image();
	image2.src = "img/arriba2.gif";
	var image3 = new Image();
	image3.src = "img/abajo1.gif";
	var image4 = new Image();
	image4.src = "img/abajo2.gif";	


function roll(img_name, img_src)
   {
   document[img_name].src = img_src;
   }

//-->


