homeon = new Image();
homeon.src = "images/red/home_on.gif";
homeoff = new Image();
homeoff.src = "images/red/home_off.gif";

nexton = new Image();
nexton.src = "images/red/next_on.gif";
nextoff = new Image();
nextoff.src = "images/red/next_off.gif";

backon = new Image();
backon.src = "images/red/back_on.gif";
backoff = new Image();
backoff.src = "images/red/back_off.gif";

introon = new Image();
introon.src = "images/red/intro_on.gif";
introoff = new Image();
introoff.src = "images/red/intro_off.gif";

scripton = new Image();
scripton.src = "images/red/script_on.gif";
scriptoff = new Image();
scriptoff.src = "images/red/script_off.gif";

// On function
function imgAct(imgName) {
    document[imgName].src = eval(imgName + "on.src");
}

// Off function
function imgInact(imgName) {
    document[imgName].src = eval(imgName + "off.src");
}