As soon as you created a CDN Resource you need to change a website HTML code to deliver your static assets through the CDN.
Click the Integration Guide tab in a CDN Resource and you will see the following data:
Origins group: origins (origin: site.com)
Canonical Name (CNAME): cdn.site.com
In order to have objects delivered through the CDN, replace your domain name with the CNAME in URLs to static files.
Please follow the instructions on configuring a CNAME record as your CDN content can be accessed only via a CNAME.
An example of integration with the G-Core CDN
<img src="http://site.com/path-to-image/image.jpg" />
<img src="http://cdn.site.com/path-to-image/image.jpg" />
The same example can be applied to other types of static files, such as CSS, JS, SWF etc.
Please note that you can’t use CDN URL (d.gcdn.co) in URLs for your static files. CDN won't work at the following URLs: <img src="http://d.gcdn.co/path-to-image/image.jpg" />
If your site uses one of well-known CMS like Wordpress, Drupal and Joomla, use plugins for CDN integration.