A term used when you're really angry with something that has happened in a short amount of time and then you take corrective action to make sure that something related will never happen again. (Being angry for a short amount of time like 20 seconds).
When someone online performs crap on your team in a game and you had to perform better than them, you also take into account their overall performance then accumulate it all at once in a snapshot fury and take that corrective action.
"Urgh, he's so fricken crap, i'm going to have to remove him!"
"He's also been crap from the past games as well!
(20 seconds later) hmm, maybe i shouldn't of done that...oh well, he won't be a bother again."
"Dude...that was like some kind of Snapshot anger/fury"
"lol yeah"