运行 Python 解释器的进程没有写入媒体目录的权限.您需要将媒体目录 chgrp 或 chown 放到与 Python 进程相同的组中，并确保至少有 g+rwx 目录和 g+rw 文件.

The process that is running your Python interpreter doesn't have permission to write into the media directory. You'll need to either chgrp or chown the media directory to the same group as your Python process, and ensure you have at least g+rwx on directories and g+rw on files.