This number might be able to be reduced if we could find out which ones users have already changed.
Can you filter this by post/upload date?
I can't easily do that, and many images are posted more than once (including quotes). The total reduction of users who updated their links so far will be <1%, so I don't think it's worth the effort (for now).
Another thing I was thinking about: changing the link to the images, without the users' authorization, wouldn't that be considered a violation of privacy?
I don't know.
I think it was preferable, at an early stage, for the process to be done via a TryNinja script, rather than doing everything via BD editing.
That works for active users, but not for the majority of posts.
Update: I
can easily sort files by upload date: all files come with a timestamp.