Ok this is copy paste from Vladimir Prelovac Bible: http://www.prelovac.com/vladimir/wordpress-optimization-guide 14. Use subdomains to share the load Most browsers are set to load 2-4 files from a domain in parallel. If you move some files to a different domain (subdomain will work) the browser will start downloading 2-4 more files in parallel. It is good idea to move your theme image files to a subdomain you create. I have created demo.prelovac.com/images and moved my theme images there. I have then changed the theme style.css to reflect the full url to the new image files. Job done! So my question is this myth or this will work for sure? And do you think i can create a subdomain and folder iamges inside it and then move all images from all my sites there and just update css and everythign will work?