Very occasionally Image Capture Extension goes rogue on me, worst I have seen is 4GB-ish. That pushed up my swap but was otherwise un-noticable in operation (I noticed it while looking for something else), but that is probably because OSX runs from an SSD so even swapping doesn't cause much of a slowdown.
Mostly it sits around the 200MB mark without issue...I can only think it is the Canon scanner sw I have installed that calls it...