I just upgraded from 6.11 to 6.23. Since then, neither the users nor myself (the administrator) can delete any photos that have been uploaded. The "Allow users to delete their own images?" under Admin Options has been set to yes and the "allow edit own posts" option for those usergroups is also set to "yes".
Under the "photo details" or "additional info" box (I don't remember exactly), there used to be links to delete or move the photo. Those are no longer there.
There is the dark red "photo options" box on the right side, but clicking on it doesn't appear to do anything - the page simply reloads with no added photo editing options.