$(document).ready(function() {
  $('div.product_gallery').SchaeferProductGallery();
});


$.fn.SchaeferProductGallery = function() {

  var gallery = this;
  $('ol li',gallery).each(function() {
    var li = this;

    $.fn.preload($('a',li).attr('href'));

    $(this).mouseover(function() {
      var bigImageSrc = $('a',li).attr('href');
      var smallImageSrc = $('img',li).attr('src');

      var bigImageSrcActive = $('img:eq(0)',gallery).attr('src');
      var smallImageSrcActive = $('a:eq(0)',gallery).attr('href');

      $('img:eq(0)',gallery).attr('src',bigImageSrc);
      $('a:eq(0)',gallery).attr('href',smallImageSrc);
      $('a',li).attr('href',bigImageSrcActive);
      $('img',li).attr('src',smallImageSrcActive);
    });
  });

}

$.fn.preload = function(src) {
  $('<img />').src = src;
}