public void initImageLoader(HTMLDocument document) {
   try {
     document.setBase(new URL(ImageLoaderCache.IMAGE_URL_PREFIX));
   } catch (MalformedURLException e) {
     log.error(e.getMessage());
   }
   setContextResource(navigator.getCurrentResource());
   document.getDocumentProperties().put("imageCache", this);
 }
 public ImageLoaderCache(Navigator navigator) {
   this.navigator = navigator;
   initBook(navigator.getBook());
 }