Upload & Sell: Off
If you "have not encountered this before", plus your profile says you shoot landscapes (not portrait or head shots), and you have no portfolio on FM to see what you offer.... I'd say do it for the experience. Maybe a nominal fee like $75 and a photo credit is about right for a person with no professional experience. If she is a big-time author who got a decent advance the book company would arrange for her to meet with a photographer they chose. If she is self-publishing, she has no budget... it's all out-of-pocket.
Seriously, forget about licensing. It may be the thing to do for some established professional photographers, but not advised for the casual shooter. Just give her a reasonable price, otherwise she will be contacting someone else. Remember that the H&S photo is going to be small and located on the back cover. Some author photos look like they posed themselves. Your photo is not going to make or break the book.