I think…I think this is a Voyager 1 image of Ganymede…although I’ve been unable to find it anywhere. If so, based on the resolution in comparison to other Voyager 1 images, possibly taken from a distance of 2.5 - 3+ million miles, ca. March 4, 1979. Although, who knows, it might’ve been taken by Voyager 2.
I should probably just stick with “Jupiter’s moon Ganymede, as viewed by Voyager in 1979.”