is no one going to explain what all the lights are
they’re impact craters! callisto is one of the most heavily cratered object in the solar system, and as far as my very basic research has just gone, the light parts are essentially iced over impact craters
so, essentially, we’re looking at something with a very frosty/icy surface. they’re bright because they reflect the sun!
"[The average human being] looks without seeing, listens without hearing, touches without feeling, eats without tasting, moves without physical awareness, inhales without awareness of odor or fragrance, and talks without thinking."