I is hard to search for threads about this in WP Support but I tried!
There was one unanswered post years ago and none of the approaches are acceptable
Update/replace images in the galleries with improved ones. e.g. an image of a Galaxy has been processed with beter contrast, the gallaxy image is linked from several posts with specific ID 123 and I need to maintain the ID
a. Delete and re-add - big nonesense (some sites really advise to do so!)
b. copy and overwrite through FTP - also nonesense if you have secured Webspace setup. all fields have UNIX rights 644 and the FTP user is not permited to overwrite and anyhow, if normal contributors want to replace.....FTP????? Hello? Not giving 200 users FTP access to my site ;-)
c. DB hacks....no comment
I would really appreciate if someone could tell me if I am just missing to see the feature or if it is really not there.
If it still does not exist, please implement this core feature soon. I refrain of touching all my files and provide 775 rights to them....