I've mentioned before, but I like this quiz, I seem to be quite good at it - with a few caveats:
-I LOVE watching films but am quite fussy about genres and my tastes aren't highbrow, there are films that are very highly regarded that I have never made it through to the end of for example
-I have eidetic visual memory - if I have sat and actually paid attention to a film, there is a high likelihood of one of the 6 stills in the quiz clicking with me
-On the other hand, I have very poor face recognition, so am not so good at the "ooh, so and so is in it, what films have they been in" type research (which I don't think is cheating, but I'm unlikely to be in a position where that particular method actually works for me)
-I'm quite good on details of certain stuff eg. fictional worlds (is a fictional corporation sign in the background), period details (costume, props, vehicles etc), location details, which is where my "haven't seen it but might be able to work it out" comes into play.
Generally, either I have seen (and paid attention to) a film and will know it fairly quickly, OR I won't have seen it and won't have a clue
Where there are a lot of films set in a particular universe or parts of a franchise, often some guesswork is involved as to which one of the series it is.