code: private static boolean isIcoHeader(final byte[] imageHeaderBytes, final int headerSize) {
      if (headerSize < ICO_HEADER.length) {
        return false;
      }
      return ImageFormatCheckerUtils.startsWithPattern(imageHeaderBytes, ICO_HEADER);
    }
docs: Checks if first headerSize bytes of imageHeaderBytes constitute a valid header for a ico image.
  Details on ICO header can be found <a href="https://en.wikipedia.org/wiki/ICO_(file_format)">
  </a>
  
  @param imageHeaderBytes
  @param headerSize
  @return true if imageHeaderBytes is a valid header for a ico image