if (document.images) {
 var p1 = new Image(100,39); p1.src = "../pennimages/penn1.gif";
 var p2 = new Image(100,39); p2.src = "../pennimages/penn2.gif";
 var p3 = new Image(100,39); p3.src = "../pennimages/penn3.gif";
 var p1b = new Image(100,39); p1b.src = "../pennimages/penn1b.gif";
 var p2b = new Image(100,39); p2b.src = "../pennimages/penn2b.gif";
 var p3b = new Image(100,39); p3b.src = "../pennimages/penn3b.gif";
}
function imgSwap(imgName,imgSrc) {
 if (document.images) { document.images[imgName].src = this[imgSrc]. src; }
}