im = new Array ('b_news', 'b_info', 'b_production', 'b_ecology', 'b_social');
  img = new Object();
  for (var i=0; i<=4; i++) {
   eval ("img." + im[i] + "=new Image");
   eval ("img." + im[i] + "_=new Image");
   eval ("img." + im[i] + ".src=" + "'images/" + im[i ] + ".gif'");
   eval ("img." + im[i] + "_.src=" + "'images/" + im[i] + "_.gif'");
  }

  function changeImage(id, action) {
   if (document.images) {
    eval  ("document.images['" + id + "'].src = img." + id + action + ".src;");
   }
  }