images = ['about-button', 'contact-button', 'events-button', 'forum-button', 'home-button',
          'movienews-button', 'podcasts-button', 'reviews-button', 'schedule-button', 'trailers-button'];

function preloadImages(){
  button = new Image();
  for(itm in images){
   	button.src = '/images/nav/' + images[itm] + '-over.gif';
  }
}

function rollover(button){
	document.getElementById(button.replace('-over','') + 'Nav').src = '/images/nav/' + button + '.gif';
}