var imagesOn = new Array();
var imagesOff = new Array();
var allLoaded = false;
var alwaysOn = "";

function preload(onImg,onSuff,offSuff) {
  var ext = ".gif"
  var suffixOn = "-hi"
  if (onSuff != null && onSuff != "")  suffixOn = onSuff;
  var suffixOff = ""
  if (offSuff != null && offSuff != "")  suffixOff = offSuff;

  if (document.images) {
    var n = 0;
    for (var i = 0; i < document.images.length; i++) {
      if (document.images[i].name) {
	var thisImg = document.images[i];
	var name = thisImg.name;
	var path = thisImg.src;
	path = path.substring(0,path.lastIndexOf('/')+1);
	//alert(name+"\n"+path);

	imagesOn[name] = new Image();
	imagesOn[name].src = path+name+suffixOn+ext;

	imagesOff[name] = new Image();
	imagesOff[name].src = path+name+suffixOff+ext;
      }
    }
  }
  allLoaded = true;

  if (onImg != null && onImg != "") {
    on(onImg);
    alwaysOn = onImg;
  }
}

function on(imgName) {
  if (allLoaded && imgName != alwaysOn)
    swap('imagesOn', imgName);
}

function off(imgName) {
  if (allLoaded && imgName != alwaysOn)
    swap('imagesOff', imgName);
}

function swap(imgArr,name) {
  if (document.images) {
    //alert(name+"\n"+document.images[name].src);
    document.images[name].src = eval(imgArr+'[name].src');
  }
}

function showLarger(img) {
  window.open('showlarger.mhtml?img='+img,'largerWin','width=600,height=400,scrollbars,resizable');
}

function showFile(img) {
  window.open('showfile.html?img='+img,'fileWin','width=600,height=400,scrollbars,resizable');
}