def IHDR(self):
        """
        IHDR chunk in PNG image
        """
        match = lambda chunk: chunk.type_name == PNG_CHUNK_TYPE.IHDR  # noqa
        IHDR = self._find_first(match)
        if IHDR is None:
            raise InvalidImageStreamError('no IHDR chunk in PNG image')
        return IHDR
IHDR chunk in PNG image