Why does pycloud reported size differ from icloud.com reported size?

[ed2050]

Any ideas why summing sizes from api.photos.all is different from iCloud's reported photo usage? In my case iCloud.com says Photos uses 41.2 GB, while summing pic.size over all items in api.photos.all only reports 18 GB. That's more than 2:1 difference.

Things I ruled out:

• It's not related to albums. I confirmed that adding and removing pics from albums doesn't alter size reported by either icloud.com or pyicloud (as expected).
• pyicloud sizes seem accurate when deleting. I removed what pyicloud says is 200 MB of photos and icloud.com reported an extra 200 MB of free space. So not sure where the extra 25 GB is.
• it's not hidden photos. I have no hidden photos.
• it's not videos. Both icloud.com and pyicloud include video files in their tallies.
• it's not any other media type. i checked all "smart" albums on icloud.com, e.g. panoramas, bursts, etc. Not only are these very small (I have a few MB in each at most), but also pyicloud already indexes what little is there.

[akarkou1]

This is possibly related to storage saving options. Check to see if the originals are stored on iCloud but downloaded as compressed. They should be under "optimize iPhone storage."