if(document.images){  
// red nav OFF state
nb_aft_off = new Image(75, 75); nb_aft_off.src = "images/nb_aft.gif";   
nb_well_off = new Image(75, 75); nb_well_off.src = "images/nb_well.gif";   
nb_cm_off = new Image(75, 75); nb_cm_off.src = "images/nb_cm.gif";   
nb_ret_off = new Image(75, 75); nb_ret_off.src = "images/nb_ret.gif";   
nb_syn_off = new Image(75, 75); nb_syn_off.src = "images/nb_syn.gif";   
nb_home_off = new Image(75, 75); nb_home_off.src = "images/nb_home.gif";   
// red nav ON state
nb_aft_on = new Image(75, 75); nb_aft_on.src = "images/nb_aft_o.gif";   
nb_well_on = new Image(75, 75); nb_well_on.src = "images/nb_well_o.gif";   
nb_cm_on = new Image(75, 75); nb_cm_on.src = "images/nb_cm_o.gif";   
nb_ret_on = new Image(75, 75); nb_ret_on.src = "images/nb_ret_o.gif";   
nb_syn_on = new Image(75, 75); nb_syn_on.src = "images/nb_syn_o.gif";   
nb_home_on = new Image(75, 75); nb_home_on.src = "images/nb_home_o.gif";   
// red nav ON state
nb_aft_about = new Image(75, 75); nb_aft_about.src = "images/nb_aft_a.gif";   
nb_well_about = new Image(75, 75); nb_well_about.src = "images/nb_well_a.gif";   
nb_cm_about = new Image(75, 75); nb_cm_about.src = "images/nb_cm_a.gif";   
nb_ret_about = new Image(75, 75); nb_ret_about.src = "images/nb_ret_a.gif";   
nb_syn_about = new Image(75, 75); nb_syn_about.src = "images/nb_syn_a.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");
        }
}
function aboutOn(imgName) {
        if (document.images) {
		document[imgName].src = eval(imgName + "_on.src");
		document["about"].src = eval(imgName + "_about.src");
        }
}
function aboutOff(imgName) {
        if (document.images) {
		document[imgName].src = eval(imgName + "_off.src");
		document["about"].src = "images/nb_flat_box.gif";
        }
}