Just putting in my two cents, but it would be better to put the distribution company there, as the uploader never really holds any rights to the image, nor is it the "source". Just the person who found it somewhere online in a press kit and decided to upload it! :)

(though that info you'd need to manually enter, or fetch from somewhere else, maybe IMDb? As we only provide the production companies).

That would be the best way but a bit hard to accomplish right now. There's a lot of images without proper attribution (because there's no field for that, licence etc) which makes using TMDB data somewhere a legal minefield.

This was recently asked here, you can see my response.