Interesting extension that can be make wiki life a little easier!
Unfortunately, it didn't work for me after I installed it and ran update.php. The #slice parser is working fine, but the #sprite parser simply displays an error box saying "SpriteSheet 1.1.5".
MW 1.27.0 / PHP 5.6.24
That is rather strange. I am not even sure how to reproduce that error. I can look into this, but I I will probably need more information. Can I get a link to the wiki where you are using this?
My bad - I finally had time to revisit this and discovered that someone had modified css to hide the file links. That's all really!