if (document.images){
	history_off=new Image
	history_on=new Image
	search_off=new Image
	search_on=new Image
	about_off=new Image
	about_on=new Image
	photographing_off=new Image
	photographing_on=new Image
	acknowledgments_off=new Image
	acknowledgments_on=new Image
	history2_off=new Image
	history2_on=new Image
	search2_off=new Image
	search2_on=new Image
	about2_off=new Image
	about2_on=new Image
	photographing2_off=new Image
	photographing2_on=new Image
	acknowledgments2_off=new Image
	acknowledgments2_on=new Image
		
	history_off.src="images/index/history_off.gif"
	history_on.src="images/index/history_on.gif"
	search_off.src="images/index/search_off.gif"
	search_on.src="images/index/search_on.gif"
	about_off.src="images/index/about_off.gif"
	about_on.src="images/index/about_on.gif"
	photographing_off.src="images/index/photographing_off.gif"
	photographing_on.src="images/index/photographing_on.gif"
	acknowledgments_off.src="images/index/acknowledgments_off.gif"
	acknowledgments_on.src="images/index/acknowledgments_on.gif"
	history2_off.src="images/history2_off.gif"
	history2_on.src="images/history2_on.gif"
	search2_off.src="images/search2_off.gif"
	search2_on.src="images/search2_on.gif"
	about2_off.src="images/about2_off.gif"
	about2_on.src="images/about2_on.gif"
	photographing2_off.src="images/photographing2_off.gif"
	photographing2_on.src="images/photographing2_on.gif"
	acknowledgments2_off.src="images/acknowledgments2_off.gif"
	acknowledgments2_on.src="images/acknowledgments2_on.gif"
}

function chgImg(imgField,newImg){
	if (document.images){
		document[imgField].src=eval(newImg+".src")
	}
	
}