Preloading Featured Images in WordPress

[RogerM]

Hi there guys!

I am at the moment trying to learn PHP as I want to get better at WordPress development and speed/performance optimization.

Right now I want to build a simple plugin (or just insert this code snippet directly into the function.php file) that allows me to preload all feature images from a blog and, at the same time, exclude these featured images from lazy loading.

This is what I got thus far...

// preloading feature images for blog posts 
     function featureimagepreload(){
         
        if(  is_single() ){
        
           $featured_img_url = get_the_post_thumbnail_url(get_the_ID(),'full'); 
           echo '<link rel="preload" as="image" href="'.$featured_img_url.'"/>';
        }
     }
 add_action( 'wp_head', 'featureimagepreload');

Thoughts?