I didn't do pictures at all for my thank-you cards for my prev wedding. I just bought a variety of boxes of small pretty cards and handwrote (all 103) people a thank you. Whilst we were opening our wedding gifts, I wrote on the back of each card what the person gave us so that I could slightly customise each thank-you note. I also sent cards to those who attended but opted not to gift (we did ask that people not give us anything).
Like Kitty, I wrote thank you letters to those who attended and customised them as much as possible. I also sent them photos of them having a good time (we had documentary style photographers).For those who couldn't attend but sent gifts, I wrote a letter and included a photo collage of us and other details like my bouquet, the Chinese wedding favour, guestbook, etc.