Have your caregivers announce themselves dramatically each time they appear after an extended absence. E.g. "Mommy's here!" Go ahead and be enthusiastic. Shout, "It's Mommy! Yippee!" Sounds simple, but it can be like a game, which makes it more rewarding than having to touch a picture ten times. This idea of labeling people is really harder for some learners than you think. Evy still sometimes calls me teacher or Daddy, and I sometimes call him Ethan or Isaac. So don't expect instant perfection.