function showlightbox(images, idx) {
  var dElem = document.getElementById("lightboxdiv");
  var dHtml = "";
  for(i=0; i< images.length; i++) {
    dHtml += "<a href='" + images[i] + "' class='thickbox' rel='lightboxgroup'>O</a>&nbsp;";
  }
  dElem.innerHTML = dHtml;
  tb_init('a.thickbox');//pass where to apply thickbox
  tb_show(null,  "http://" + document.location.hostname + images[idx], "lightboxgroup");
}