if (document.images) {
  onasD = new Image();
  onasD.src = "images/1_onas.jpg";
  onasL = new Image();
  onasL.src = "images/1a_onas.jpg";

  sluzbyD = new Image();
  sluzbyD.src = "images/2_sluzby.jpg";
  sluzbyL = new Image();
  sluzbyL.src = "images/2a_sluzby.jpg";

  reseniD = new Image();
  reseniD.src = "images/3_reseni.jpg";
  reseniL = new Image();
  reseniL.src = "images/3a_reseni.jpg";

  referenceD = new Image();
  referenceD.src = "images/4_reference.jpg";
  referenceL = new Image();
  referenceL.src = "images/4a_reference.jpg";

  kontaktyD = new Image() ;
  kontaktyD.src = "images/5_kontakty.jpg";
  kontaktyL = new Image() ;
  kontaktyL.src = "images/5a_kontakty.jpg";
}

function load(imagename, objectsrc) {
  document.images[imagename].src = eval(objectsrc + ".src");
}