The online library features over 650 images of the trust's landscapes, gardens and stately homes throughout England, Wales and Northern Ireland, some of which have been taken by top professional photographers.
A spokesperson said the trust had always had an image library that it used for its own purposes and sold for media use, but this was the first time the library had been available to the public.
She said the trust had no idea how much the initiative would raise so was unable to set targets. "It is something we are trying, "she said. "Because it is new we don't know how it is going to go, but we hope it is going to be a good earner. Once it gets going we will be able to set targets.
Prices for the prints will range from £15 to £120. The images will also be available to send as e-cards.