So I spent a little time on google today and compiled a 2mb "pic pack" of most of the moons of the solar system.
I also renamed my favorite "planet" pictures to make it easier to set up the sol system (as for whatever reason it always defaults to a blank blue ball for all the planets).
This isn't 100% complete by any means, especially considering the small "moon" (little more then fragments really) of Jupiter and Saturn, as well as the fact that some of the tiny moons around Neptune and Uranus are little more then blurs on most pictures. Therefore, if any picture is missing, I recommend using the "chunk" moon pictures from Jupiter or Saturn's moons as they tend to be detailed enough to be interesting but "chunky" enough to be accurate enough.
So, for most of the planets & moons it's a pretty straight forward naming convention. The first three letters of the name = picture name.
ex. Atlas = atl.jpg, Ganymede = gan.jpg
There are a few exceptions as by the time I got towards the end a few things started repeating. Hopefully it's still obvious what is what, but here's the "exception" list:
cab.jpg = Caliban (Uranus)
ttn.jpg = Titania (Uranus)
phb.jpg = Phoebe (Saturn)
prt.jpg = Proteus (Neptune)