// Images array
var aryImages = new Array(2);

aryImages['aktualnosci_off'] = "../cms/File/menu/przycisk_aktualnosci_1.gif";
aryImages['aktualnosci_on'] = "../cms/File/menu/przycisk_aktualnosci_2.gif";


for (i=0; i < aryImages.length; i++) {
  var preload = new Image();
  preload.src = aryImages[i];
}

function swap(imgIndex, where) {
  document[where].src = aryImages[imgIndex];
}