I'm working on the tag wikis for our most popular tags, and wrote a description for post-processing. When I got down to photo-editing, though, I found that basically the same description had already been written for that tag.
Post-processing is the process (and art) of adjusting a previously-captured image to obtain a desired look. It encompasses everything from simple whole-image adjustments to detailed per-pixel touch-up work.
and then I found:
Photographic editing is the process of reworking an original photo, either produced by film or digital, to create the artistic vision of the photographer.
Should these tags be merged? Or, is there some distinction that we should emphasize?
Update: I was all set to accept Stan's answer, but then I notice that of the 54 questions tagged photo-editing on the site so far, exactly one of them (Attribution in a digital print?) has the "photo editor as a job" sense. And there's one other that might apply (since it applies to my answer, but the question seems to intend it the other way) — Image processing & editing: what is an "unmanipulated" image?.
Or just make it a synonym of post-processing and have people who meant it in the job sense choose something else.
I think this is important, because the combination of the two tags would make it our fourth-top overall tag, tied with nikon and after lens, equipment-recommendation, and canon. Having post-processing questions split buries them much further down the list, in conflict with this:
It is my strong belief that the tags page is an essential map of what your community is, and is not, about.