I'm trying to enhance the performance of my store from many aspects, so I would like to create a cookie-less subdomain on my server hosting Magento 1.7 so as to server image, CSS and JS files from there. I know how to setup the subdomain, and also configure Magento from System > Configuration > Web so as to pickup the JS and media from a URL of the cookie-less subdomain.
However, I haven't understood this: when I upload image files for a new or existing product, Magento will normally store them under the directory /media/catalog/product found at Magento's root directory. How the cookie-less subdomain's directory storing the images will get informed about the new images?
As per my understanding, Images will be stored first in your media folder and then they will sync to your CDN. Now it can remove images from your media folder but depends on your CDN configurations.
Thanks for your answer but I don't mean to setup a CDN with Magento. I just mean to create a subdirectory on my server hosting Magento so as to server from there my static content. The advantage of this solution is just to avoid the overhead of cookies. It doesn't have the other advantages of a CDN.