I’m not fully sure of what I’m looking at here.  The labels say that these pictures are of Saturn, so my guess is that most of the top-left half of the frame is the night side of Saturn, and that the stationary white specks are some sort of camera artefacts.  The moving white specks are background stars, and (this is the interesting bit) you can see how the light from them gets refracted through the upper part of Saturn’s atmosphere: a couple of them quite noticeably move upwards a little as they emerge from behind the planet.  That’s if I’ve understood it right.
Photographed by Cassini, 13 July 2012.

I’m not fully sure of what I’m looking at here.  The labels say that these pictures are of Saturn, so my guess is that most of the top-left half of the frame is the night side of Saturn, and that the stationary white specks are some sort of camera artefacts.  The moving white specks are background stars, and (this is the interesting bit) you can see how the light from them gets refracted through the upper part of Saturn’s atmosphere: a couple of them quite noticeably move upwards a little as they emerge from behind the planet.  That’s if I’ve understood it right.

Photographed by Cassini, 13 July 2012.