[Michael Georges]

National Geographic often buys the "rights to reproduce", while the rights to the photo itself remains with the photographer.

I used to buy clip art and photography for use in publications.

Most of the time, the cost is dependent on the "number of impressions" you intend to use the work in. For instance, if you want to use a photo in your corporate brochure, the cost to use the image is based on the number of brochures you intend to make. Costs can also be based on time - i.e., we bought some images for unlimited use in our marketing materials for a period of one year.

Now, this was for stock photography. In the case of a photographer who sells their pictures for publication, you should expect the cost to be quite a bit higher because that is their art and they sell it as such.

You might want to drop his rep a line and find out if he is even amenable to your using the image, and if so, how much. It is a nice painting and you might be able to sell it if you can get their consent.