function preload() {
  n1 = new Image();      
  n1.src = "images/logo_.gif"; 
  n2 = new Image();      
  n2.src = "images/blym.gif"; 
  n3 = new Image();      
  n3.src = "images/menu_bg_.gif"; 
  n4 = new Image();      
  n4.src = "images/menu_bg.gif"; 
}