iPod Photo Cache?

I’ve noticed that every once in a while TM will claim it’s backing up ~19 GB of data. Despite a fast TM disk that does take a while. It especially takes too long when I need to get out of the door asap. And since I know that I haven’t changed that much since the last backup an hour ago I started wondering.

Thanks to awesome TimeTracker I now know it’s actually backing up 16.7 GB that come from the folder
iPod Photo Cache in
~/Pictures/Photos Library.photoslibrary.
Interesting, I don’t have an iPod anymore. I do have an iPhone and an iPad. I sync both to my Photos.app. I don’t use iCloud for my photos, but I do use the old My Photo Stream. So a couple of questions.

  1. Can I get rid of that cache?

  2. If that’s not a good idea, can I exclude it from TM? Since it’s just a cache I suppose it’s not terribly important to include it in my TM backups. I’m assuming it could be recreated as long as the Photos.app data (i.e. my photos) is being backed up which it is.

  3. Where does it actually come from? Due to its name I would think it’s old (from the old iPhoto days maybe?) but since it’s being backed up though TM I have to assume it’s being modified. What’s doing that?

  4. Why does TM claim it’s backing up 19 GB when actually it’s just under 17 GB? I remember back in the day when TM still left meaningful output in the easy to read console log files, there was sometimes a mention of padding. Is this difference that padding? And if so, what purpose does it serve? I have ample TM disk space so it’s not a problem, but I’m curious.

Yes. I have no such folder in my Photos library.

Yes, you can explode any folder from backup.

I cannot check right now, but I believe there is a checkbook in iTunes somewhere that controls this. It’s possible there was a checkbox that is no longer there that is still set to true. Something about optimizing photos.

The displayed size is always just an estimate or best guess. I find it’s generally about right, but in the past it has been widely off (like I’m backing up 1-2GB and it says there is 150GB to backup).