function changeImage(areaId,image) {
	MapSwap(image,"oversrc");
}

function changeImageBack(areaId,image) {
    MapSwap(image);
}

function MapSwap(el,which){
  el.src=el.getAttribute(which || "origsrc");
  if (el.style.visibility == "hidden") {
  	el.style.visibility = "visible";
  }
  else {
  	el.style.visibility = "hidden";
  }
}

function MapSwapSetup(){
  var x = document.getElementsByTagName("img");
  for (var i=0;i<x.length;i++){
    var oversrc = x[i].getAttribute("oversrc");
    if (!oversrc) continue;
    // preload image
    // comment the next two lines to disable image pre-loading
    x[i].oversrc_img = new Image();
    x[i].oversrc_img.src=oversrc;
    // set event handlers
    x[i].onmouseover = new Function("MapSwap(this,'oversrc');");
    x[i].onmouseout = new Function("MapSwap(this);");
    // save original src
    x[i].setAttribute("origsrc",x[i].src);
  }

}