I used landscape photographs for my covers, fiddled about with them on the pc until they looked like paintings, and used the results. Not only did I end up with conformity of image - different photographs but used the same techniques for each book - but they did not detract from the story. An artist's impression of your contents can be a trifle skewed, don't you think? As I set my books in a period that existed 200 years ago, all I had to do was to find a scene that had remained unaltered over that period of time. Also my books contain lots of characters - depicting any one of them sets that image in your reader's eye. I hate reading a book about some sensitive artist when the front cover has an image of Superman's double displayed on it! It's hard to identify the character because you end up imagining the hero in the form of the artist's depiction - F. J. Warren
The cover art on 'Rashi's Daughters' isn't a painting of the real Joheved; she was neither rich nor famous enough for that. However DaVinci's art is in the public domain, and I have a license for 50,000 uses of the hi-res file from Getty Images. It cost me around $1000 if I remember correctly. I hired an award-winning design firm, Lightbourne, to do the cover - Maggie Anton
I have an inexpensive program called Thumbs Plus that lets me mess with the overall look of the picture. I then used good old Paint to put on the title and byline. Simple-easy.
I started with a vintage photo of a cowboy and his horse. I cropped it to the right proportions then I changed it to sepia-tone. Messed around with fonts and such and came up with a pretty decent cover using only low-cost tools. - Marva Dasef