Animated GIFs can have up to 256 colors & they are not interactive.
jAni is a lightweight jQuery plugin for animating background images which can be an alternative to animated GIFs (in some cases).
It simply changes the position of a long background image in given distances & speed.

The plugin has few options for controlling it:

• start, stop, pause
• speed
• loop on/off
• dimensions of the frames

As it will require JavaScript to be enabled, using jAni combined with other JavaScript events (like animating a better-quality Ajax loader) would be very functional.
Website: http://www.ajaxblender.com/jani.html
Demo: http://www.ajaxblender.com/script-sources/jani/demo/...