Animated GIF

You've probably already seen animated GIFs on the Internet. While they're a relatively archaic format and have a number of limitations (such as being restricted to 256 or fewer colors), they can be a quick and fun way to show something in motion: sort of like a brief video or slide show.

While you can't upload animated GIFs directly into Second Life (GIF isn't a supported texture upload file format), you can show them on a prim's face with Shared Media.

How do I make animated GIFs?

There are numerous tools: googling for "animated gif maker" yields various results.

Advanced content creators may already be familiar with using tools already in their workflow, like Adobe Photoshop, to create animated GIFs.

Certain video apps can export a movie as a series of still images, or directly export as an animated GIF.

Marketplace

The Second Life Marketplace supports animated GIFs, [as detailed here] link to Grant's blog post.