var nav01=new Image();
var nav02=new Image();
var nav03=new Image();
var nav04=new Image();
var nav05=new Image();
var nav06=new Image();
var nav07=new Image();
var nav08=new Image();
var nav09=new Image();
var nav10=new Image();
var nav11=new Image();
var nav12=new Image();
var nav13=new Image();
var nav14=new Image();
var nav15=new Image();
var nav16=new Image();
var nav17=new Image();
var nav18=new Image();

function NavPic() {
  nav01.src="../graphics/but-m01b.jpg";
  nav02.src="../graphics/but-m01a.jpg";
  nav03.src="../graphics/but-m02b.jpg";
  nav04.src="../graphics/but-m02a.jpg";
  nav05.src="../graphics/but-m03b.jpg";
  nav06.src="../graphics/but-m03a.jpg";
  nav07.src="../graphics/but-m04b.jpg";
  nav08.src="../graphics/but-m04a.jpg";
  nav09.src="../graphics/but-s01b.jpg";
  nav10.src="../graphics/but-s01a.jpg";
  nav11.src="../graphics/but-s02b.jpg";
  nav12.src="../graphics/but-s02a.jpg";
  nav13.src="../graphics/but-s03b.jpg";
  nav14.src="../graphics/but-s03a.jpg";
  nav15.src="../graphics/but-s04b.jpg";
  nav16.src="../graphics/but-s04a.jpg";
  nav17.src="../graphics/but-topb.jpg";
  nav18.src="../graphics/but-topa.jpg";
}


function blPic(item,action) {
  if (action) {
    document.images["but-"+item].src="../graphics/but-"+item+"b.jpg";
  }
  else {
    document.images["but-"+item].src="../graphics/but-"+item+"a.jpg";
  }
	return true;
}