Inefficient Thumbnail generation for external libraries about immich

[mertalev]

Files are read multiple times for thumbnail generation regardless of whether it’s from an internal or external library. I recently experimented with combining them so a file is read once and both the preview and thumbnail are written from that. It ended up using more RAM, though, so I shelved it. Maybe I should revisit it and see if I can get it leaner.

[bo0tzz]

Fwiw - there's definitely a possibility for improvement here, but we can't really specifically provide support for weird rclone mounts. On normal filesystems this current situation is slower but not a "high egress cost" kind of problem.

[NickIAm]

l thought that might be the case. I understand my setup isn't exactly supported, but it does work quite well. I think if each file is read multiple times maybe it could be done all at once. ie produce all the different thumbnail sizes at once on the same file for one after the other instead of doing multiple passes over the entire dataset. It could potentially help in other situations with caching filesystems like ZFS.