Steve,

 Each of the cards has to have the suit symbol in the top and bottom corners, just like on a normal playing card. I have written below each image what suit has to correspond on the cards themselves. Sorry the queen is so small, it's the biggest pic I could find of her. If you can find a bigger one, by all means use it.

Jess

Alice - Diamonds	Dodo - Diamonds	Rabbit - Spades
Hatter - Clubs	Duchess - Hearts	Queen - Hearts
Caterpillar - Spades