My son started with movies early. We took him to see Babies when he was a baby - he loved it. Only a couple films per year, with earplugs. Documentaries and cartoons are best. I found that he does much better when he's surrounded by other kids than when the theater is empty. And he's a sensitive kid so he handles the happy-go-lucky films better than the others.
I feel like movies can be a fun experience for kids. Short bursts of this type of screen time are fine, IMO. Use it as something to talk about

Spoiler alert:
I tried taking him to Chimpanzee but the scene where the baby chimp loses his mother was too loud and scary (and frankly too sad for me) so we had to leave early. But he did great at The Lorax and Charlottes Web and A Dolphin Tale and other similar upbeat films.
I think the movie theater experience can make emotions be felt more strongly than TV, so keep that in mind.
Follow Mothering