The history of tarot is something of a mystery. The first sets appeared in Italy in the 14th century and were used for playing games. An occultist called Court de Gebelen who lived in the late 1700s is credited with being the first to popularise their use as a divination aid.
Until the 19th century tarot decks only had symbols on the minor cards, reserving pictures for the court cards and trumps. The Rider-Waite deck and the deck designed by Aleister Crowley were among the first with pictures on all the cards.
The popularity of the Rider-Waite deck is probably due to the fact that the pictures can easily be used to tell a story, which helps if you are doing a divination showing a passage of time - the past, present and future for example.
Here are some useful links on the history of tarot cards:
http://www.tarothermit.com/
http://www.tarotpedia.com/wiki/Main Page
http://roswell.fortunecity.com/leehigh/340/shadow/shadow5.htm