function newImage(arg) {

  if (document.images) {

    rslt = new Image();

    rslt.src = arg;

    return rslt;

  }

}

function changeImages() {

  if (document.images && (preloadFlag == true)) {

    for (var i=0; i<changeImages.arguments.length; i+=2) {

      document[changeImages.arguments[i]].src = changeImages.arguments[i+1];

    }

  }

}

var preloadFlag = false;

function preloadImages() {

  if (document.images) {

    t_01  = newImage("images/top-btn-domu-p.jpg");

    t_02  = newImage("images/top-btn-mail-p.jpg");

    t_03  = newImage("images/top-btn-mapa-p.jpg");

    t_04  = newImage("images/menu-btn-bar-p.jpg");

    t_05  = newImage("images/menu-btn-herna-p.jpg");

    t_06  = newImage("images/menu-btn-kontakty-p.jpg");

    preloadFlag = true;

  }

}