My deduction is that flashes that large in the film are due to what I think is called lens flare, or perhaps over exposure... (everything else in the image seems rather dark) but I could be wrong, I'm no photo pro.
Although, it seems to me that when you get close they scale far too large either way.
That's from the front page (not sure who titled it p51-vs-fw190.jpg, as that is clearly a P-47...), one of those sprites seems to take up a good quarter of the right wing (I realize there are multiple hits there, but I have no pictures of my own of a single ping right now, searching through film).
I feel that if it were the human eye, like I think we are trying to simulate in this game, the flashes would be very small, about the size of the bullet if maybe a tad bigger. But that's my personal opinion and preference, I think it would give a much better idea of how many hits we are getting.