Films seem to be particularly well suited to having Tumblr blogs dedicated to them.
I’ve been following Movies in Frames for what feels like ages. “One movie - four frames. That’s it.”. The quality is a little variable, but it’s generally well worth following.
Newer yet is Behind My Back, which takes stills where you’re invited to share the viewpoint of the film’s protagonists.
Finally, and a new find today, is Movie Barcode, which turns every film into a single image, recording the predominant colours throughout.
Enjoy browsing their respective archives.