if(document.images) {
	
	var nav_btt1 = new Image();
	var nav_btt2 = new Image();
	
	var nav_ctw1 = new Image();
	var nav_ctw2 = new Image();
	
	var nav_cre1 = new Image();
	var nav_cre2 = new Image();
	
	var nav_fee1 = new Image();
	var nav_fee2 = new Image();
	
	var nav_pri1 = new Image();
	var nav_pri2 = new Image();
	
	var nav_enl1 = new Image();
	var nav_enl2 = new Image();
	
	var nav_bac1 = new Image();
	var nav_bac2 = new Image();
	
	var nav_nex1 = new Image();
	var nav_nex2 = new Image();
	
	nav_btt1.src = "/wgbh/nova/images02/nav_backtotop.gif";
	nav_btt2.src = "/wgbh/nova/images02/nav_backtotop_on.gif";
	
	nav_ctw1.src = "/wgbh/nova/images02/nav_closethiswindow.gif";
	nav_ctw2.src = "/wgbh/nova/images02/nav_closethiswindow_on.gif";
	
	nav_cre1.src = "/wgbh/nova/images02/nav_icon_credits.gif";
	nav_cre2.src = "/wgbh/nova/images02/nav_icon_credits_on.gif";
	
	nav_fee1.src = "/wgbh/nova/images02/nav_icon_feedback.gif";
	nav_fee2.src = "/wgbh/nova/images02/nav_icon_feedback_on.gif";
	
	nav_pri1.src = "/wgbh/nova/images02/nav_icon_print.gif";
	nav_pri2.src = "/wgbh/nova/images02/nav_icon_print_on.gif";
	
	nav_enl1.src = "/wgbh/nova/images02/nav_side_enlarge.gif";
	nav_enl2.src = "/wgbh/nova/images02/nav_side_enlarge_on.gif";
	
	nav_bac1.src = "/wgbh/nova/images02/nav_icon_back.gif";
	nav_bac2.src = "/wgbh/nova/images02/nav_icon_back_on.gif";
	
	nav_nex1.src = "/wgbh/nova/images02/nav_icon_next.gif";
	nav_nex2.src = "/wgbh/nova/images02/nav_icon_next_on.gif";
}