Another thing I have seen done is to use a projector to enlarge and trace an image and then go back and add a traditional media to it. Then of course there are light boxes…
To me it is really about what the goal of the artist is. Is it to save production time? Is it to get a great likeness (which is beyond their skill)? It could be a lot of things. I feel it is all valid.
As to calling it original work… Wow, that is harder isn’t it? I mean if you do it based off of life drawing, or the grid method, it is still as close to an exact image as you can get… either way, to me it is all art. I am not sure how I feel as to the “original” question.
As I grew up my mother, who was a pretty darn good artist, always told me that “copying” (to her that was using any reference other than life), was cheating… I was a very literal kid so I was loathe to use reference. I now feel that really held me back a lot.
Like I said, to me, it’s all in what you (the artist) want to get out of it.