code: def _pack_asf_image(mime, data, type=3, description=""):
      
      tag_data = struct.pack('<bi', type, len(data))
      tag_data += mime.encode("utf-16-le") + b'\x00\x00'
      tag_data += description.encode("utf-16-le") + b'\x00\x00'
      tag_data += data
      return tag_data
docs: Pack image data for a WM/Picture tag.