'Updates the width and height fields of a webp image with vp8x chunk.'

def _update_webp_vp8x_dimensions(self):

    size = len(self._image_data)
    if (size < 30):
        raise BadImageError('Corrupt    WEBP    format')
    (self._width, self._height) = struct.unpack('<II', self._image_data[24:32])
    if ((self._height is None) or (self._width is None)):
        raise BadImageError('Corrupt    WEBP    format')
