I've looked the poster script idea, but it isn't working for me.
I wanted to use Google with a title, year and director. That would be enough to ensure valid results, get the advanced search features (like character set conversions). Plus, it would be very easy to parse a Google page and get the links to the full-sized images (along with their sizes on preview).
Unfortunately Google uses HTTPS, and PVD automatically adds HTTP to the beginning of any search that doesn't have it at the beginning.
Personally, I'm just going to continue to manually find the posters I want.