var arrow1_g = new Image();
var close_g = new Image();
var travel_g = new Image();
var t9_g = new Image();
var t11_g = new Image();
var t13_g = new Image();
var plus = new Image();
var minus = new Image();

preload_pics();

function preload_pics () {
  arrow1_g.src = "pics/arrow1_g.gif";
  close_g.src = "pics/close_g.gif";
  travel_g.src = "pics/travel_g.gif";
  t9_g.src = "pics/head/9_g.jpg";
  t11_g.src = "pics/head/11_g.jpg";
  t13_g.src = "pics/head/13_g.jpg";
  plus.src = "pics/plus.gif";
  minus.src = "pics/minus.gif";
}