if (document.images) {
  imagec1on = new Image();
  imagec1on.src = "navbutns_contact/bt_contact_representatives_on.gif";
  
  imagec2on = new Image();
  imagec2on.src = "navbutns_contact/bt_contact_head_office_on.gif";
  
  imagec3on = new Image();
  imagec3on.src = "navbutns_contact/bt_contact_feedback_on.gif";
    
  imagec1off = new Image();
  imagec1off.src = "navbutns_contact/bt_contact_representatives.gif";
  
  imagec2off = new Image();
  imagec2off.src = "navbutns_contact/bt_contact_head_office.gif";
  
  imagec3off = new Image();
  imagec3off.src = "navbutns_contact/bt_contact_feedback.gif";
  
}

function changeImages() {
  if (document.images) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
    }
  }
}