Ask HN: Image search API that allows automated querying?

I've been (unsuccessfully) looking for a service that will allow me to find images (specifically movie posters) via a web-based API, and that allows automated queries.

Some options I've already investigated:

Google, Yahoo, Bing, ALIPR: all of these services specifically ban queries of any sort unless they are specifically initiated (and editable) by an end-user.

Internet Video Archive: returns 'images' associated with a movie, but none of them are posters.

IMDB: Bans automated querying.