Where Glue generates the CSS for you, csssprites seems to expect you to first add all the sprites as backgrounds to the CSS rules you want to use, and then annotate them with comments and then process your CSS to replace those rules with suitable rules.

Glue on the other hand generates the CSS for you, but expect you add a CSS class to the elements that should contain the sprites (or you can modify the generated CSS of course).

csssprites is much more complicated to use but will take image alignments into account which makes it the more useful tool.