My son's preschool is fabulous about taking pictures and loading them on the internet (secured). I plan on making a small scrapbook with a photo from each month and a "Thank you for showing/helping/encouraging etc me by...." & a funny saying he said for me throughout the year.
He just turned 3 its amazing what he says about the things he does each day. I still can't believe that Miss Mendy "showed" him how to do a somersault, but I guess anythings possible :) I just know I wouldn't be out there rolling around on the grass (or maybe I would I don't know). I love how excited he was in general about going to his class, and just want to convey that excitement to them somehow.. I'm also debating on whether to include a 5-10 giftcard for Target or Starbucks...
Don't know if you have any pictures, but I would say something just to show you appreciate their time and hard-work would be more than enough. I feel these days teachers of any level are not told how much they are truly appreciated :)
Good Luck let us know what you decided to do!!