if (document.images) {
	home_on = new Image();
	home_on.src = "images/home_on.png";
	home_off = new Image();
	home_off.src = "images/home_off.jpg";
	
	bio_on = new Image();
	bio_on.src = "images/bio_on.png";
	bio_off = new Image();
	bio_off.src = "images/bio_off.jpg";
	
	clinic_on = new Image();
	clinic_on.src = "images/clinic_on.png";
	clinic_off = new Image();
	clinic_off.src = "images/clinic_off.jpg";
	
	medicine_on = new Image();
	medicine_on.src = "images/medicine_on.png";
	medicine_off = new Image();
	medicine_off.src = "images/medicine_off.jpg";
	
	chinese_on = new Image();
	chinese_on.src = "images/chinese_on.png";
	chinese_off = new Image();
	chinese_off.src = "images/chinese_off.jpg";
	
	links_on = new Image();
	links_on.src = "images/links_on.png";
	links_off = new Image();
	links_off.src = "images/links_off.jpg";
	
	contact_on = new Image();
	contact_on.src = "images/contact_on.png";
	contact_off = new Image();
	contact_off.src = "images/contact_off.jpg";

}

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");
    }
  } // end of document.images if
} // end of mouseover sub-navigation