Here is a video of how kids can use sprites. Kids often come from Scratch where all the pictures are sprites. In ZIM we usually use Sprite to mean animated pictures... although there is the concept of a TextureMap where sprites can show a bunch of pictures. And... loading pictures from a Sprite for an Emitter can be more efficient due to a single read to the GPU.
Thanks @karelrosseel82 for the prompting. We have added this to the Sprite section of the Help on the ZIM Kids Slate page.