public byte[] loadBytes(String filename) {
    InputStream is = createInput(filename);
    if (is != null) return loadBytes(is);

    System.err.println("The file \"" + filename + "\" " +
                       "is missing or inaccessible, make sure " +
                       "the URL is valid or that the file has been " +
                       "added to your sketch and is readable.");
    return null;
  }