function preload_menu() {
  //note: must use different variable names so image STAYS loaded in memory
  preload1 = new Image();
  preload1.src = "graphics/menu/coming_on.gif";
  preload2 = new Image();
  preload2.src = "graphics/menu/members_on.gif";
  preload3 = new Image();
  preload3.src = "graphics/menu/ratings_on.gif";
  preload4 = new Image();
  preload4.src = "graphics/menu/home_off.gif";
  preload5 = new Image();
  preload5.src = "graphics/menu/money_on.gif";
  preload6 = new Image();
  preload6.src = "graphics/menu/store_on.gif";
  preload7 = new Image();
  preload7.src = "graphics/menu/email_on.gif";
}