Stabbey IS right, though.
The white formations that are seen there look a lot like clouds, and clouds can't exist without atmosphere, and moons are too small to sustain atmosphere. Plus, the blue surface makes it look like an ocean planet. Not to mention the size.
That's not true, lots of moons have atmospheres, Enceladus for example is tiny and has a rather thick one. The difference between a moon and a binary planet is where the centre of mass of the two bodies is, so if it's between the two planets it's a binary planet where each planet rotates around each other (Pluto and Charon for example --though they're no longer planets), if the certre of mass is within one of the planets then one is a satellite/moon of the other (eg. Earth and our moon) (note that there are other definitions of this though).
For all we know Rivellon (or where this picture is from) is a moon of the object in the picture! Anyway, I don't mean to be so pedantic, I just think this stuff is interesting.
