To rename the URL of an image in WordPress for use with a Content Delivery Network (CDN), you can use the following steps:
Install and activate the "CDN Enabler" plugin. This plugin allows you to easily set up and manage a CDN for your WordPress site.
In the WordPress dashboard, go to Settings > CDN Enabler.
In the "CDN Settings" section, enter the URL of your CDN in the "CDN URL" field. This should be the base URL of your CDN, without the file path of the image.
In the "Include Directories" field, enter the file path of the images that you want to serve from the CDN. For example, if your images are stored in the "wp-content/uploads" directory, you would enter that path in this field.
Click the "Save Changes" button to save your settings.
The plugin will now automatically rewrite the URLs of your images to point to the CDN. You can verify that the CDN is working by checking the source code of your site and looking for the CDN URL in the image URLs.
Keep in mind that this process will only work for images that are stored in the directories specified in the "Include Directories" field. If you have images in other locations, you will need to manually update their URLs or use a different method to serve them from the CDN.
Additionally, you may need to clear your site's cache and the cache of your CDN provider to see the changes take effect.