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1. Login your WordPress
2. Install and activate plug-in W3 Total Cache plugs-in
3. In the menu performance, select General Settings and scroll down to CDN
   1. Check the box “Enable CDN”
   2. Choose CDN Type: Generic Mirror
   3. Save All Settings
4. Now you can enter your CDN name menu performance under CDN
   1. Under Configuration enter the Enter CDN name in the textbox behindunder Configuration Replace site’s hostname with: <CDN name> in textbox under Configuration
      
   2. Click Test Mirror to check the CDN is functioning properly
   3. Save all setting

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-The CDN can be accessed using HTTP or HTTPS. Make sure to use HTTPS (SSL), if your website uses an HTTPS:// address. Otherwise you will likely end up with mixed-content warnings in your browser (images being loaded from http links).

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or check in your browser:

Firefox: Tools-> > Web developer-Web >Web developer>Web Console
Chrome: View-> Developer > Developer >Developer>Developer Tools Tab: Console
Safari: Develop-> Show >Show Error Console

For example: www.example.com/aaa.jpg

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