function rollOverImage(id){
    hideAll();
    document.getElementById(id).style.display = "block";
}
function hideAll(){
    document.getElementById("image1").style.display = "none";
    document.getElementById("image2").style.display = "none";
    document.getElementById("image3").style.display = "none";
    document.getElementById("image4").style.display = "none";
    document.getElementById("image5").style.display = "none";
}