function imageByName(imgName, aWindow) {
  var i;
  images = aWindow.document.images;
  for (i=0; i < images.length; i++) {
    var src = images[i].src.split('/').reverse();
    if (src[0].indexOf(imgName) != -1) {
      return images[i];
    }
  }
  return false;
}