var image1 = new Image();
image1.src = "moveup.gif";
var image2 = new Image();
image2.src = "movedown.gif";
var image3 = new Image();
image3.src = "an1.gif";
var image4 = new Image();
image4.src = "an2.gif";

function roll(img_name1, img_src1, img_name2, img_src2)
	{
	document[img_name1].src = img_src1;
	document[img_name2].src = img_src2;
	}