if (document.images) {
	arrow1a=new Image(23,33); arrow1a.src = "images/arrow1a.gif";
	arrow1b=new Image(23,33); arrow1b.src = "images/arrow1b.gif";
	arrow2a=new Image(23,33); arrow2a.src = "images/arrow2a.gif";
	arrow2b=new Image(23,33); arrow2b.src = "images/arrow2b.gif";
	
	arrow3a=new Image(23,12); arrow3a.src = "images/arrow3a.gif";
	arrow3b=new Image(23,12); arrow3b.src = "images/arrow3b.gif";
	arrow4a=new Image(23,12); arrow4a.src = "images/arrow4a.gif";
	arrow4b=new Image(23,12); arrow4b.src = "images/arrow4b.gif";	
	
	}
	function SwapImg(imgnum, imgsrc) {
    	if (document.images) {
			document.images['but'+imgnum].src=imgsrc.src;
			return true;
		}
	}