if (document.images) {

cpoon = new Image();
cpoon.src = "images/cpo2.gif";
cpooff = new Image();
cpooff.src = "images/cpo.gif";

apspon = new Image();
apspon.src = "images/apsp2.gif";
apspoff = new Image();
apspoff.src = "images/apsp.gif";

guardexon = new Image();
guardexon.src = "images/guardex2.gif";
guardexoff = new Image();
guardexoff.src = "images/guardex.gif";

omnion = new Image();
omnion.src = "images/omni2.gif";
omnioff = new Image();
omnioff.src = "images/omni.gif";

merlinon = new Image();
merlinon.src = "images/merlin2.gif";
merlinoff = new Image();
merlinoff.src = "images/merlin.gif";

}

function imgOn(imgName) {
if (document.images) {
document[imgName].src = eval(imgName + "on.src");       
}
}

function imgOff(imgName) {
if (document.images) {
document[imgName].src = eval(imgName + "off.src");        
}
}