Saturn may not be the biggest planet in the solar system, but it's still a giant. Some of its companions though are anything but. Some of the smaller moons are glorified asteroids that were lucky enough to enter a stable orbit around the planet making them hard to spot not only from Earth, but even from close by.
The Cassini probe, which has been spending its last few years circling around Saturn and snapping photos with every occasion it got, managed to shoot a very nice view of Saturn and its rings along with three of its smallest moons, Atlas, Prometheus and Epimetheus, all packed relatively close together.
From left to right they are: Prometheus, which is 86 kilometers or 53 miles across, inside the F ring; Atlas, which is only 30 kilometers or 19 miles across, between the A and F rings; and Epimetheus, which is 113 kilometers or 70 miles across.
Epimetheus is shown here 1.5 times brighter than it really is, to make it easier to see, and Atlas' brightness has been improved three times compared to Saturn's rings. If you're having trouble spotting them all the same, check out the labeled image in the gallery.