function newImage(arg) {
  if (document.images) {
    rslt = new Image();
    rslt.src = arg;
    return rslt;
  }
}

function changeImages() {
  if (document.images && (preloadFlag == true)) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
    }
  }
}

var preloadFlag = false;
function preloadImages() {
  if (document.images) {
	index_05_over = newImage("images/index_05_over.gif");
	index_05_down = newImage("images/index_05_down.gif");
	index_07_over = newImage("images/index_07_over.gif");
	index_07_down = newImage("images/index_07_down.gif");
	index_09_over = newImage("images/index_09_over.gif");
	index_09_down = newImage("images/index_09_down.gif");
	index_11_down = newImage("images/index_11_down.gif");
	index_11_over = newImage("images/index_11_over.gif");
	index_21_over = newImage("images/index_21_over.gif");
	index_21_down = newImage("images/index_21_down.gif");
	index_23_over = newImage("images/index_23_over.gif");
	index_25_over = newImage("images/index_25_over.gif");
	index_25_down = newImage("images/index_25_down.gif");
    preloadFlag = true;
  }
}