code: public ImageIcon getImage( String key ) {
          ImageIcon image = imageMap.get(key);
          if (image == null) {
              image = createImage(key);
              imageMap.put(key, image);
          }
          return image;
      }
docs: Get an image for a certain key.
  
  <p>
  <b>The only keys to be used are the static strings in this class!!</b>
  </p>
  
  @param key
  a file key, as for example {@link ImageCache#DATABASE_VIEW}.
  @return the image.