img_on = new Image(150,184);
img_on.src="lolo1.jpg";
img_off = new Image(150,184);
img_off.src="lolo2.jpg";
  

function over_image(parm_name)
    {
        document[parm_name].src = eval(parm_name + "_on.src");
    }
function off_image(parm_name)
    {
        document[parm_name].src = eval(parm_name + "_off.src");
    }