Here is an excerpt from a webpage on the history of the Tarot:
Arthur Edward Waite is credited with the renaissance of the Tarot in the Twentieth Century. He commissioned artist Pamela Coleman Smith to create what he called the "rectified" Tarot. Created by a member of secret societies also known as a revered mystic, Waite's version has been widely accepted as the standard, and is by far the most popular deck of the century, rich in symbolism and easily understood due to the simple nature of the artwork.
In the opinion of many learned Tarot enthusiasts, the most significant change the deck has experienced is Smith's treatment of the Minor Arcana. Hers are the first "pip" cards to contain images depicting the meaning of the cards. These graphics allow readers to explain the significance of each cards nuance to querents who, in most cases, have never encountered the cards before. This artistic trend can be traced through the majority of the decks produced after the Rider-Waite (1910), and Smith's influence is readily recognized, as many of the images echo her drawings.