function loadImage() {
    image01 = new Image ();
    image01.src = "Image/button_home.gif";
    image02 = new Image ();
    image02.src = "Image/button_home_white.gif";

    image03 = new Image ();
    image03.src = "Image/button_map.gif";
    image04 = new Image();
    image04.src = "Image/button_map_white.gif";

    image05 = new Image();
    image05.src = "Image/button_mail.gif";
    image06 = new Image();
    image06.src = "Image/button_mail_white.gif";


    image100 = new Image();
    image100.src = "Image/arrow_grey.png";
    image102 = new Image();
    image102.src = "Image/arrow_blue.png";

}
function changeHome() {
    document.images.home.src=image02.src;
}
function backHome() {
    document.images.home.src=image01.src;
}

function changeMap() {
    document.images.map.src = image04.src;
}
function backMap() {
    document.images.map.src = image03.src;
}
function changeContact() {
    document.images.contact.src = image06.src;
}
function backContact() {
    document.images.contact.src = image05.src;
}


function changeArrow1() {
    document.images.arrow1.src = image102.src;
}
function backArrow1() {
    document.images.arrow1.src = image100.src;
}
function changeArrow2() {
    document.images.arrow2.src = image102.src;
}
function backArrow2() {
    document.images.arrow2.src = image100.src;
}
function changeArrow3() {
    document.images.arrow3.src = image102.src;
}
function backArrow3() {
    document.images.arrow3.src = image100.src;
}