you're probably better off watching the series to get better pictures as to the clow cards are very hard to find full color pictures of, of course the clow cards you can get but those are like yellowy not the true colors.
try www.anipike.com and go into the anime/manga series. Find card captors, and browse the fan sites and such. It will take a while to look through them all, but theres a ton of pics scattered through out them. ^_^