if(document.images) {
pics = new Array(); 
pics[1] = new Image();
pics[1].src = "images/nav_home_page1.jpg";
pics[2] = new Image();
pics[2].src = "images/nav_home_page2.jpg";

pics[3] = new Image();
pics[3].src = "images/nav_about_us1.jpg";
pics[4] = new Image();
pics[4].src = "images/nav_about_us2.jpg";

pics[5] = new Image();
pics[5].src = "images/nav_surveyors1.jpg";
pics[6] = new Image();
pics[6].src = "images/nav_surveyors2.jpg";

pics[7] = new Image();
pics[7].src = "images/nav_customers1.jpg";
pics[8] = new Image();
pics[8].src = "images/nav_customers2.jpg";

pics[9] = new Image();
pics[9].src = "images/nav_contact1.jpg";
pics[10] = new Image();
pics[10].src = "images/nav_contact2.jpg";
}

function changer(from,to) {
if(document.images) {
document.images[from].src = pics[to].src;
}
}