Essentially, what was said above.
Until the primary IT administrator has the time from his regular job(s) and life and whatnot to attempt to restore the pictures from a backup, which will probably be a laborious manual effort (so as not to wipe out any new attachments), the old pics and attachments of various types will remain in whatever state they are currently in.
The only way that can change other than the above is if each person that posted such pics and attachments has saved their stuff and goes thru the laborious process of deleting the broken version and re-uploading the original again, for every post they made, one at a time.
I myself would have hundreds of images to fix, at least, and I am not going to put that effort into it unless I have a guarantee of some sort that it is not going to be able to happen again (meaning that multiple people have local copies of the entire databases both forum and attachments, and a way of easily restoring them individually or globally).
Well, actually, in theory, the other board administrator could get hold of the primary, get a physical copy of the uncorrupted backup(s), and then perform the restore, but I doubt he has any time available to do it, either. No one else I am aware of has admin access to the database to do such file-by-file replacements.
In theory it could also be scripted, if anyone knows how, but that would replace every attachement with whatever was in teh backup (even if the current one is uncorrupted and the one in the backup is not).
It's a lot of work no matter how you look at it, unless the backup/restore functions happen to be automated enough to allow this kind of thing easily, which I doubt. I fully expect the functions would be made only to backup and restore the *entire* database at once, and I have no idea what havoc that would cause with attachments and images added *after* the backup was created.