I've tried watching some movies in my target language (German), but I find that the actors speak so fast that I can barely follow. However, I do like the idea of trying to associate words with images instead of mentally trying to translate everything (and making me miss most of the movie).

I find comics to be helpful.  You get that same words/images association but you can read at your own speed and get used to the vocabulary.  Maybe with a few months more practice I will attempt to watch movies in German again.

Some movies can be helpful. Others can be of little help at all.

It depends upon the movie.

For example,  many Movie Musicals  can be helpful, such as:

  "My Fair Lady,"     "Oklahoma,"    "Oliver,"    "West  Side  Story"  or   "Hair".

Of course, unless a person  prints out the Lyrics for the songs in these movies,

they are not  very helpful.  I have the Lyrics  for "Oliver" and have used it successfully to tutor students in English.

I think that is very good to develop my english. Often i watch "Friends", sometimes they speaks fast, but i try to understand. 

My target language is English and yes, they are helpful for passive knowledge thought I watch more tv shows than movies. Let me explain: I watch using english subtitles and playing pause and rewind when I don't understand any word or I listen a new word or concept. Yeah, I know it's weird this way of watching tv but it helps me a lot. I've been doing this for 2 years everyday and I believe I understand 80-85 percent. on the other hand when I watch some video from engvid.com I don't use any subtitle and I understand everything they say. 

Of course, there are some shows like Chicago PD more difficult. I don't understand the main character next to nothing so I stopped to watch the episode. 

My next challenge, this summer, is watching without subtitles.

Regards,

Alfonso