What is the CSS Sprite Performance gain for repeat visitors?

Question

I have a site that has a large menu and each item on the menu has an icon. I have been looking into implementing a CSS sprite to speed it up, but I am wondering what the performance gain will be. My site is not open to the public so the users will almost always be repeat, so is it worth implementing or should I just rely on caching?

Answer 1

Unless your site has heavy non-repeat traffic, there probably won't be much of a noticeable performance gain at all. Are you currently having performance problems? If not, there's probably no need to prematurely optimize such a relatively minor thing.

Answer 2

How sure are you that, in the future, portions of the site won't be

• Made public
• Expand the private audience
• Get new menus

All of those are reasons you may want to consider doing this up-front. I don't know your situation, but for some developers the first two items might be implemented suddenly as a business decision, and the programmer never even hears about it a manager comes back later asking for a way to improve performance on the site. Or maybe it never even gets that far: maybe the site loses users because of slowness and management never hears about it either.

Now, since you already have code that works I wouldn't worry about it too much. But when putting sites together initially it's something to remember.

Answer 3

I think that the major question you should be asking, is are your users pleased with the responsiveness of the site. If they aren't, and there isn't a greater underlying problem causing this, then you might use this change.

There's a nice article on the topic at List Apart http://www.alistapart.com/articles/sprites/