It's (probably) an unstable video, so you take the data from each frame for some large fraction of a second and you can create an image that's somewhere between

It's (probably) an unstable video, so you take the data from each frame for some large fraction of a second and you can create an image that's somewhere between the total number of available pixels in all the frames and the number in a single frame. Note: While the spacecraft itself is moving at incredible speeds, the maneuvers themselves are slow enough that several (to many with a high speed camera) images can be combined.