About The Card Images Used On The Keystone:
Tarot card images used throughout The Keystone are from the Tarot deck illustrated by Pamela Colman Smith under the direction of R:.W:. Arthur Edward Waite, published in 1909, and are thus in the Public Domain.
Card images pictured are from scans of that original 1909 deck, and are not sourced from images U.S. Games Systems claims copyright over. To view this public domain Tarot deck or learn more about it visit the Wikipedia page discussing it here.
You can learn more about A.E. Waite, and his works here.
You can learn more about Pamela Colman Smith and her works here.