Sprite Master Web have support for CSS.
Sprite Master supports MaxRects algorithm for aligning and ordering your sprite files in the best and minimum way.
Resizes spritesheet to optimum size. If you need your output to be in power of two sizes, deactivate Non Power of Two feature.
Sprite Master saves your spritesheet documents. Document files stores all the sprite files and sprite sheet parameters.
Trim your sprites and all empty spaces will be dismissed. You can add empty space around sprites with padding features.
You can rename your sprites in the Sprite master. Thus, your export files will contains these names.