// Preload images and perform mouseovers
function preloadImages() {
 if (document.images) {
  var imglist = document.images;
  for(var i=0; i < imglist.length; i++)
  {
   if(document.images[i].name.indexOf('nav_') != -1)
   {
    preloadImage = new Image();
    preloadImage.src = 'http://bluescreensystems.com/images/nav/n' + document.images[i].name.substr(4) + '_mo.jpg';
   }
  }
 }
}

function changeImage(img_name) {
 if(document.images) {
  if(document.images[img_name].src.indexOf('_mo') != -1)
   document.images[img_name].src = 'http://bluescreensystems.com/images/nav/n' + document.images[img_name].name.substr(4) + '.jpg';
  else
   document.images[img_name].src = 'http://bluescreensystems.com/images/nav/n' + document.images[img_name].name.substr(4) + '_mo.jpg';
 }
}

// Preload images and prepare anything necessary for other functions
function init() {
 preloadImages();
}