Mammal Pictures of the Year Screensaver shows multiple images of mammals in a slideshow. Among the animals you will find dolphins, elephants, big cats, squirrels, monkeys, elephants, foxes, and pets, to name but a few. The images look good, they come in different sizes and a different transition effect is used for each of them, but you cannot customize them. You are not allowed to customize the order of the images, and they are shuffled by default. Unfortunately, the screensaver doesn't have any sounds or music, and neither can you add your own, which is really a shame.
The screensaver doesn't have any configuration options whatsoever. The settings menu only shows a description of the screensaver, credits, and terms and conditions. The only option you will find is a "Mute" checkbox, which is useless, because the screensaver doesn´t include music or sounds.
In short, if you are looking for a simple screensaver with images of animals, Mammal Pictures of the Year Screensaver may work for you.