Haven't done anything with photos yet...but my average flight video is about 1.5 gigs.
So...1 flight for a 2GB card. Just grab a 64 GB card, they are suoer cheap, and you'll never fill it up if you remember to clear it off only every once in awhile.
I use 2x class 10 8gig. $10bucks ea and cover you for 3 or more flights.
32 gigs is overkill. You want to unload footage to your pc ASAP incase something happens to your phantom.