Admin Forum:Difference between wikia and nocookie.net url

I was just working to keep my site's page load latency low and found these URLs redirecteing to the same location. Is there any difference between them? If so, which one is the best to use in CSS?
 * http://images.wikia.com/seiyuu/ko/images/4/44/Sidebar-top-bottom.png
 * http://images4.wikia.nocookie.net/seiyuu/ko/images/4/44/Sidebar-top-bottom.png
 * http://images4.wikia.nocookie.net/__cb20120827043023/seiyuu/ko/images/4/44/Sidebar-top-bottom.png


 * nocookie.net is a cookieless domain. This means that your site cookies aren't sent to the server, thus reducing the request size. So technically the nocookie site should be a little faster. Don't know the difference between the bottom 2 though. - Tjcool007 (Wall) 09:17, August 27, 2012 (UTC)


 * Second URL is for the last image, while third URL is somewhat a "permalink" to that version of the image. When you upload a new image, the previous version may still be on the cache (both server and in your browser). When this happens, wikia generates a new URL so your browser gets the new version bypassing the cache, and that kind of url is cached longer than the second URL. -Category:Ciencia Al Poder (talk) -WikiDex 09:26, August 27, 2012 (UTC)


 * Thanks for your attention, Tjcool and Ciencia! If I don't misunderstand, it's 3 > 2 > 1 by fastest then.


 * What's the first URL then? I'm not sure I've ever seen one of those. --


 * Well I get this URL when left clicking on the thumbnail image of the [[File:Somefile]] page. Like  http://images.wikia.com/central/images/e/ed/Galler3.jpg  for File:Galler3.jpg. Though I have no idea for the origin of this URL.

Maybe the first URL is a Community Central specific thing. Which would explain why I've never seen those in the wild. In any case the first URL comes with a cookie. Which is odd. There's gotta be a reason for that... --


 * Hmm.. you might be right for most of english wiki sites, but the wikis outside seems having different structure: test this one for example, or an another random international wiki.


 * Maybe we're reading too much into this. The first type of URL is probably the default MediaWiki image URL and Wikia simply did not manage to replace those absolutely everywhere with nocookie.net URLs...