When I was editing books at Harvard, an author came in one time and asked that a piece of antique Japanese silk be used for the jacket design. "Do you have one we can borrow?" my boss asked politely. That put an end to that and taught me that authors, by and large, should leave book production up to the pros.
The primary function of a dust jacket is to draw the attention of potential buyers. When Where the Light Falls first appeared in bookstores and was turned face out, the woman's stare caught your eye across the room just like that of Edmund Dulac's fallen angel would for Helen Beauclerk's Love of the Foolish Angel. I could enjoy the graphic impact; but I also found it funny that (a) the woman on the cover of Where the Light Falls is costumed from a much later date and (b) the bridge shown, the Pont Alexandre III, does not appear in the novel.
The publisher had been kind enough to ask whether I had any suggestions. Mine was to use a detail from John Singer Sargent's In the Luxembourg Gardens, which was from exactly the right period, by an artist who figures in the novel, depicting a couple in a location that also does. Actually, I had always fantasized about a wraparound jacket using the whole painting, but I suspected that if they took me up on it, they would want just the couple on the front. As it turned out, they ignored me totally, which was fine (no antique Japanese silk).
Nevertheless, I have always slightly regretted that the cover tells the reader nothing about what's in my book and is in some ways misleading. Edmund Dulac illustrated The Love of the Foolish Angel throughout, so his jacket design is part of an aesthetic package. In 1950, George Salter recommended that designers read entire manuscripts whether the publisher asked them to or not (see Martin Salisbury, The Illustrated Dust Jacket: 1920–1970, p. 12). If they all did, and if publishers considered jacket design more than short-term advertising, readers would be much better able to judge a book by its cover!