if (document.images)
  {
    inspection_on = new Image(81,31);
    inspection_on.src ="./images/button_inspection_down.gif";
    inspectors_on = new Image(80,31);
    inspectors_on.src ="./images/button_inspectors_down.gif";

    inspection_off = new Image(81,31);
    inspection_off.src ="./images/button_inspection_up.gif";
    inspectors_off = new Image(80,31);
    inspectors_off.src ="./images/button_inspectors_up.gif";
  }