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

function preload() {
  var prefix = ""
  var suffixOn = "-hi"
  var suffixOff = ""
  var ext = ".png"

  if (document.images) {
    var n = 0;
    for (var i = 0; i < document.images.length; i++) {
      if (document.images[i].name && document.images[i].name.indexOf('_') == -1) {
        var thisImg = document.images[i];
        var imgName = thisImg.name;
        var path = thisImg.src;
	if (imgName.indexOf('bars') != -1) continue;

        path = path.substring(0,path.lastIndexOf('/')+1);

        if (imagesOn[imgName] == null || imagesOn[imgName] == "") {

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

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

function on(imgName) {
  swap('imagesOn', imgName);
}

function off(imgName) {
  swap('imagesOff', imgName);
}

function swap(imgArr, imgName) {
  if (document.images && allLoaded) {
    document.images[imgName].src = eval(imgArr+'[imgName].src');
  }
}

function popBigWin(url) {
  window.open(url, 'imgWin', 'width=750,height=750,resizable,scrollbars');
}