function setRollOver( id , newfilepath ){
    var img = document.getElementById( id );
    var oldfilepath = img.src;

    var newImg = new Image();
    newImg.src = newfilepath;

    img.onmouseover = function(){
        img.src = newfilepath;
    }
    img.onmouseout = function(){
        img.src = oldfilepath;
    }
}

function setSwapImages(){
    setRollOver("logo", "images/logoOn.gif");
    setRollOver("home", "images/backToTagaOn.gif");
}