By ‘staying still’ I meant the satellites were constantly moving in orbit..............
Yup. And that means that their camera has to be able to move. Any satellite with a direct line of sight to the point of interest on the surface can get video of it. It may be at an angle, but it can get it. Satellites do not have to be directly overhead to get vision of a point, nor do they have to stop and go geostationary to surveil an area.
Or put another way, a satellite in a sufficiently high orbit can, while passing over Los Angeles and heading west, still send you live, real time video of New York City. Perhaps not terribly useful video of NYC depending on the camera resolution, but it can still see and send you video of NYC.