According to researchers at Microsoft, images aren't just classified into the still and moving sort. There's also a third kind, which they've termed a Cliplet.
Imagine, if you will, a still image that's taken from a single frame of a movie, but with one small area of the screen that still contains the full moving version. In the classic example on Microsoft's web site, there's a scene of a fountain with people walking past. The main part of the Cliplet consists of a still image showing motionless people in a neat pose. And yet the fountain continues to flow.
If you're a keen producer of digital images or video, and you want to explore this potential new way of presenting your work, check out the Microsoft web site. You can find out more, and download a free program to create your own Cliplets, at http://research.microsoft.com/en-us/um/redmond/projects/cliplets/. The program runs only on Windows 7, and is available in 32- and 64-bit flavours.