I don't know of a program that has multiple decks available to it, but if you have an iPad or an Android tablet there are increasing numbers of decks available for cheap. I've got the Prairie Tarot, Ator Tarot, and a few others that were under $3 each. I've also got a couple more, including Legacy of the Divine and Touchstone that were between $5 and $8 I think. One of the things I particularly like about the tablet apps is that many of them allow you to see the card as a full screen image. Imagine a card shown two to four times the usual card size. It helps me really "sink" into the images and enjoy the details.
By the way, I think the imagery is primary. I read intuitively, by what I see and and feel from the imagery itself. I don't even bother reading the traditional meanings anymore, but I read mostly for my own insight into my subconscious and personal growth.
If you don't have a tablet, I know that Kat Black's Touchstone tarot used to be available for readings online. I'd have to hunt around for it, but try searching on her name, or the deck name, or on 78 friends, which I think is the name of one of her sights. Its a lovely deck.
Good luck!!!