I'm not an expert, but I'll share what I know.
They do sometimes do retouched autopsy photos. The issue is that depending on the condition of the face, the degree of swelling from injuries, and so forth, LE may not feel that the death photo accurately reflects what the person looked like in life. Since the point of the reconstruction/composite/whatever they call it is to produce an image that will be recognized by people the victim knew that may mean making a sketch or reproduction of some kind.
A composite sketch is put together by a police artist using a set of standard features, usually the FBI's Facial Identification Catalog. Usually there's a witness giving the description and picking out the features. Here's a link that explains the process:
COMPOSITE DRAWINGS
In this case, I'm not sure whether the artist worked from a witness who had seen Jane while she was alive, or if the artist worked by looking at the victim's face or the autopsy photos. Probably a combination.
A reconstruction usually works from the postmortem photos or the victim's remains, often using the skull as the basis for detailed analysis of bone structure, depth of fat and muscle tissue, and all the rest.
Artist's revision would mean that the new artist worked from the composite, giving it a more realistic look. I've seen some very useful versions of this where the artist gives a variety of possibilities for what the person might have looked like--dressed up, different lengths and colors of hair, different body weights, etc. These look pretty basic.
The current trend is for very realistic, almost photographic reconstructions, like the ones CarlK does. But when I took a forensics class a couple of years ago, they said that often the exaggerated "caricature" style produces better results than more realistic images, because friends or relatives recognize things like "that looks like old Joe with his big ears. whatever happened to him? Maybe I'd better call." Whereas if a photo-like picture isn't exactly right, it sometimes gets dismissed.
