Cleaning out orphaned images

Every now and then I have stumbled upon images that are no longer in use in any doc. Most recently while working on https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/28346.

Should there be an effort to find and delete all the orphaned images? It might be something that newer team members could work on from time to time?

Update: I have found a way to do this that shouldn't take too long. About halfway finished already.