def read_metadatablockpicture( data ):
	"""Extract picture from a METADATA_BLOCK_PICTURE"""
	off = 8 + int.from_bytes( data[4:8], 'big' )
	off += 4 + int.from_bytes( data[off:off+4], 'big' ) + 16
	size = int.from_bytes( data[off:off+4], 'big' )
	return data[4+off:4+off+size]