[jpm48]

Have a look at OpenImageIO it may help. The otool can do lots, and if not you may be able to use the API's (C++ or Python) https://openimageio.readthedocs.io/en/latest/

[JKCalhoun]

Thanks, so many tools to try. On MacOS I ran:

% brew install openimageio

But have not yet put it to task with my large files.