if (document.images) {
   es_pas = new Image();
   es_pas.src = "pics/es_pas.gif";
   es_akt = new Image();
   es_akt.src = "pics/es_akt.gif";
   visa_pas = new Image();
   visa_pas.src = "pics/visa_pas.gif";
   visa_akt = new Image();
   visa_akt.src = "pics/visa_akt.gif";
   his_pas = new Image();
   his_pas.src = "pics/his_pas.gif";
   his_akt = new Image();
   his_akt.src = "pics/his_akt.gif";
   mtiede_pas = new Image();
   mtiede_pas.src = "pics/mtiede_pas.gif";
   mtiede_akt = new Image();
   mtiede_akt.src = "pics/mtiede_akt.gif";
   matk_pas = new Image();
   matk_pas.src = "pics/matk_pas.gif";
   matk_akt = new Image();
   matk_akt.src = "pics/matk_akt.gif";
   kuvia_pas = new Image();
   kuvia_pas.src = "pics/kuvia_pas.gif";
   kuvia_akt = new Image();
   kuvia_akt.src = "pics/kuvia_akt.gif";
   yht_pas = new Image();
   yht_pas.src = "pics/yht_pas.gif";
   yht_akt = new Image();
   yht_akt.src = "pics/yht_akt.gif";
   pal_pas = new Image();
   pal_pas.src = "pics/pal_pas.gif";
   pal_akt = new Image();
   pal_akt.src = "pics/pal_akt.gif";

   fp_pas = new Image();
   fp_pas.src = "pics/fp_pas.gif";
   fp_akt = new Image();
   fp_akt.src = "pics/fp_akt.gif";
   vapp_pas = new Image();
   vapp_pas.src = "pics/vapp_pas.gif";
   vapp_akt = new Image();
   vapp_akt.src = "pics/vapp_akt.gif";
   hist_pas = new Image();
   hist_pas.src = "pics/hist_pas.gif";
   hist_akt = new Image();
   hist_akt.src = "pics/hist_akt.gif";
   geo_pas = new Image();
   geo_pas.src = "pics/geo_pas.gif";
   geo_akt = new Image();
   geo_akt.src = "pics/geo_akt.gif";
   trav_pas = new Image();
   trav_pas.src = "pics/trav_pas.gif";
   trav_akt = new Image();
   trav_akt.src = "pics/trav_akt.gif";
   pics_pas = new Image();
   pics_pas.src = "pics/pics_pas.gif";
   pics_akt = new Image();
   pics_akt.src = "pics/pics_akt.gif";
   con_pas = new Image();
   con_pas.src = "pics/con_pas.gif";
   con_akt = new Image();
   con_akt.src = "pics/con_akt.gif";
   fbck_pas = new Image();
   fbck_pas.src = "pics/fbck_pas.gif";
   fbck_akt = new Image();
   fbck_akt.src = "pics/fbck_akt.gif";
}

function show(image) {
   if (document.images) {
      document.images[image].src = eval(image + "_akt.src");
   }
}

function hide(image) {
   if (document.images) {
      document[image].src = eval(image + "_pas.src");
   }
}