if (document.images)
{

  var about_1 = new Image ();
  about_1.src = "images/about_off.gif";
  
  var about_2 = new Image ();
  about_2.src = "images/about_on.gif";
  
  var employ_1 = new Image ();
  employ_1.src = "images/employ_off.gif";
  
  var employ_2 = new Image ();
  employ_2.src = "images/employ_on.gif";
  
  var services_1 = new Image ();
  services_1.src = "images/services_off.gif";
  
  var services_2 = new Image ();
  services_2.src = "images/services_on.gif";

  var links_1 = new Image ();
  links_1.src = "images/links_off.gif";
  
  var links_2 = new Image ();
  links_2.src = "images/links_on.gif";

  var email_1 = new Image ();
  email_1.src = "images/email_off.gif";
  
  var email_2 = new Image ();
  email_2.src = "images/email_on.gif";

  var next_1 = new Image ();
  next_1.src = "images/next_off.gif";
  
  var next_2 = new Image ();
  next_2.src = "images/next_on.gif";

  var back_1 = new Image ();
  back_1.src = "images/back_off.gif";
  
  var back_2 = new Image ();
  back_2.src = "images/back_on.gif";

}

function ChangeImage(imgDocID,imgObjName) 
{
        if (document.images) 
        {
      document.images[imgDocID].src = eval(imgObjName + ".src");
        }
}