The largest known galaxy is 4 light years across.

I am trying to get my head around the fact if a telescope takes a photo of the galaxy the distance from one side to the other is so far you are seeing the closest part at one point in time and the opposite side of it at another point in time. (due to 4 light year difference in time for the last to arrive at camera from each side of the galaxy)

How does this not mess up the photo?
Do they take photos of these things over years and then merge them together to get a proper photo of it at one time?
Or is every photo of a galaxy ive ever seen a kind of timelapse showing different sections of the galaxy at different times all blurred together?