if (document.images) {
  
  image1a = new Image();
  image1a.src = "/images/button_about.gif";
  image1b = new Image();
  image1b.src = "/images/button_about_r.gif";
  
  image2a = new Image();
  image2a.src = "/images/button_system.gif";
  image2b = new Image();
  image2b.src = "/images/button_system_r.gif";
  
  image3a = new Image();
  image3a.src = "/images/button_store.gif";
  image3b = new Image();
  image3b.src = "/images/button_store_r.gif";
  
  image4a = new Image();
  image4a.src = "/images/button_contact.gif";
  image4b = new Image();
  image4b.src = "/images/button_contact_r.gif";
  
  image5a = new Image();
  image5a.src = "/images/button_home.gif";
  image5b = new Image();
  image5b.src = "/images/button_home_r.gif";

  image6a = new Image();
  image6a.src = "/images/button_join.gif";
  image6b = new Image();
  image6b.src = "/images/button_join_r.gif";
  
  image7a = new Image();
  image7a.src = "/images/button_news_2.gif";
  image7b = new Image();
  image7b.src = "/images/button_news_2_r.gif";
  
  image8a = new Image();
  image8a.src = "/images/button_demonstration.gif";
  image8b = new Image();
  image8b.src = "/images/button_demonstration_r.gif";
	
  image9a = new Image();
  image9a.src = "/images/button_resources.gif";
  image9b = new Image();
  image9b.src = "/images/button_resources_r.gif";
  
  image10a = new Image();
  image10a.src = "/images/button_faq.gif";
  image10b = new Image();
  image10b.src = "/images/button_faq_r.gif";
  
  sys_image1a = new Image();
  sys_image1a.src = "/images/button_features.gif";
  sys_image1b = new Image();
  sys_image1b.src = "/images/button_features_r.gif";
  
  sys_image2a = new Image();
  sys_image2a.src = "/images/button_competition.gif";
  sys_image2b = new Image();
  sys_image2b.src = "/images/button_competition_r.gif";
  
  sys_image3a = new Image();
  sys_image3a.src = "/images/button_addons.gif";
  sys_image3b = new Image();
  sys_image3b.src = "/images/button_addons_r.gif";
  
  image11a = new Image();
  image11a.src = "/images/button_performance.gif";
  image11b = new Image();
  image11b.src = "/images/button_performance_r.gif";
  
  image12a = new Image();
  image12a.src = "/images/button_viewperf.gif";
  image12b = new Image();
  image12b.src = "/images/header_pastperf_r.gif";
  
  image13a = new Image();
  image13a.src = "/images/button_sitemap.gif";
  image13b = new Image();
  image13b.src = "/images/button_sitemap_r.gif";

  subscribe_a = new Image();
  subscribe_b = new Image();
  subscribe_a.src = "/images/button_subscribe.gif";
  subscribe_b.src = "/images/button_subscribe_o.gif";

  unsubscribe_a = new Image();
  unsubscribe_b = new Image();
  unsubscribe_a.src = "/images/button_unsubscribe.gif";
  unsubscribe_b.src = "/images/button_unsubscribe_o.gif";
}

function changeImage(imgDocID,imgName) 
{
    document[imgDocID].src = eval(imgName+ '.src');
}