So I love the idea of making personalized "thank you" notes.
I've gotten a couple in the mail from weddings I attended and loved having a wedding photo so quickly to hang on the fridge/dorm room wall/etc. Also, it can be cheaper than ordering more matching cards, depending on how you print them!
Etiquette says to send out thank you notes as you receive gifts, which is good taste, the right thing to do, etc. But obviously you don't have the cute cards with your wedding photos yet. I've already gotten a wedding present and am not getting married for another year and a half!
Solution: Take a similar photo at an engagement shoot, or even just go to a scenic spot with a decent camera/smartphone & a friend/tripod.
Make your own cards through a photo website (make sure you have rights to use the photo file!) or print them out nice cardstock with a Publisher thank-you note template.
BOOM. Personalized thank you notes, ready for any early wedding/engagement presents!