The following picture is
not animated. Your
eyes are making it move.
To test this, look at the
black centre of each
circle and it will stop
moving. But move your
eyes to the next centre
and the previous one
will start moving again.

The picture is called
"Rotating snakes" and
was created by
A. Kitaoka. You can find
more of his artwork here.

(Click on photo to enlarge)