if (document.images) {

bckImSrc=new Array();
bckImSrc[0]="../img/back0.gif";
bckImSrc[1]="../img/back2.gif";
bckImSrc[2]="../img/back2.gif";
bckImSrc[3]="../img/logo3sm.gif";
bckImSrc[4]="../img/logo3sl.gif";

backImg=new Array();
for (var i=0; i<=bckImSrc.length; i++) {
backImg[i]=new Image();
backImg[i].src=bckImSrc[i];}}

function b(n) {
if (document.images) {
document.back.src=backImg[n].src;}
return true;}