If you really want to blow your mind, you should look at the automated spriting in Compass: http://compass-style.org/help/tutorials/spriting/

Or look at Glue : )

https://glue.readthedocs.org/en/latest/

There's also http://csssprites.org/ (SmartSprites). The web based tools aren't really in the same category as Compass, Glue and SmartSprites - they can't be part of an automated build, so someone is going to have a repetitive manual task to do. Ok for a one-off, but annoying in the long term.

+1 for compass, but one problem with it is that (AFAIK) you can only do png sprites, so you can't do them for animated gif (for spinners and the likes).

Is there a solution for automated sprites with Sass when you can't use Compass?