same problem here (using 0.2. rc2)
the cover art isn't grabbed from imdb (they only have very small pictures) but from amazon. that also explains why the description / actors and that stuff is correct but the cover isn't.
my example:
movie: the rock
imdb url:
http://www.imdb.com/title/tt0117500/
cover:
http://www.amazon.com/gp/product/ima...F8&n=130&s=dvd
the cover is from the dvd "schoolhouse rock" which is the first search result when you do a DVD-search for "the rock" at amazon.com
edit:
just found out: when you do a DVD-search (as above) "the rock" is in 5. place. when you do a "general" amazon.com search, "the rock" DVD is the first result (which would lead to the right cover)