If you’re having trouble getting your images indexed by Google, and you’re using the combination of a CDN (content delivery network) and Yoast SEO on WordPress, it might be because Yoast SEO’s sitemap is pointing to the non-CDN versions, while Google can only see the CDN versions mentioned on your site.
But it’s very easy to fix. Add this snippet to your functions.php file, replacing the MYDOMAIN.com and CDN.MYDOMAIN.com sections with whatever matches your setup.
// Telling Yoast XML Sitemap to redirect images to CDN versions
function wpseo_cdn_filter( $uri ) {
return str_replace( '//MYDOMAIN.com', '//CDN.MYDOMAIN.com', $uri );
}
add_filter( 'wpseo_xml_sitemap_img_src', 'wpseo_cdn_filter' );
When the XML sitemap is regenerated, it should now point the image files to the CDN versions.
It then can take a while for Google to pick up on the change and start indexing your images–it doesn’t usually happen overnight.
Extra Tip: Add CDN to Search Console
Google also recommends that you add the CDN’s subdomain to your Search Console properties so that they can alert you to any crawling errors they come across there.
Things Worth Knowing
If something goes wrong with the functions.php file, it can create a white screen for your website. So it’s a good idea to back up your functions.php before you start so that you have a working copy to quickly restore. Restoring the backup version should get the site back up immediately.
