Andy --
As you have discovered, the deletion of old attachments does not occur in real time.?I'm not personally aware of how frequently groups.io purges old attachments from groups over quota or how much additional "grace" storage is provided.?
If you are having problems uploading files/photos and want to get ahead of this see?
/g/GroupManagersForum/wiki/Deleting%20attachments,%20files%20and%20photosHope this helps,
Bruce
--
The system Help is your friend.??
/static/help