Kan man få 2 forskellige billeder til at skifte ved OnMouseOver?

Kan man lave om i dette script, så to billeder skifter ved hver aktivering?

<script language="JavaScript">
if (navigator.appVersion.indexOf("2.") != -1){
    check = false;
    }
if ((navigator.appVersion.indexOf("3.") != -1) && (navigator.appName.indexOf("Explorer") != -1)){
    check = false;
    }
else {
    check = true;
    }
if (check == true){
image1= new Image();
image1.src = "activity/menu1_off.gif";
image1on = new Image();
image1on.src = "activity/menu1_on.gif";
image1stay = new Image();
image1stay.src = "activity/menu1_on.gif";

}

imageStay = ""

function imageon(name){
    if (imageStay != name){
            document[name].src = eval(name + "on.src");
    }
}
function imageoff(name){
    if (imageStay != name){
            document[name].src = eval(name + ".src");
    }
}

function on(name){
        if (check == true){
    imageon(name);
    }
}
function off(name){
        if (check == true){
    imageoff(name);
    }
}

function stay(name){
    if (check == true){
    document[name].src = eval(name + "stay.src");
    if (imageStay != name){
        if (imageStay != ""){
            document[imageStay].src = eval(imageStay + ".src");
        }
    }
    imageStay = name
    }
}

var NN3 = false;


</script>


<a href="activity.html" onmouseover="on('image1');" onmouseout="off('image1')" onClick="stay('image1');">
        <img src="activity/menu1_off.gif" width=120 height=19 border=0 alt="" name="image1">