var Imgi = new Array();

function preload(url) {
   if (document.images) {
      var i = Imgi.length;
      Imgi[i] = new Image();
      Imgi[i].src = url;
   }
}

function load_pics() {
  preload('../images/submenu.png');
  preload('../images/menu_02_a.jpg');
  preload('../images/menu_03_a.jpg');
  preload('../images/menu_04_a.jpg');
  preload('../images/menu_05_a.jpg');
}