image1 = new Image();
image1.src = "images/menu_o_nas_on.gif";

image2 = new Image();
image2.src = "images/menu_oferta_on.gif";

image3 = new Image();
image3.src = "images/menu_galeria_on.gif";

image4 = new Image();
image4.src = "images/menu_kontakt_on.gif";