I have a plugin that checks if the post contains external images and if so it will download and replace it with a local image. Now the problem is it doesn’t download images if the image tag is written like this

<img src="https://www.wptricks.com/wp-content/uploads/2020/12/sample_b3355819c05a45ec67b8aa7de5dad94b218f7836.jpg" referrerpolicy="no-referrer">

Here’s the plugin code

add_action('publish_post', 'fetch_images');

function fetch_images( $post_ID )  
{   
    //Check to make sure function is not executed more than once on save
    if ( defined('DOING_AUTOSAVE') && DOING_AUTOSAVE ) 
    return;

    if ( !current_user_can('edit_post', $post_ID) ) 
    return;

    remove_action('publish_post', 'fetch_images');  
        
    $post = get_post($post_ID);   

    $first_image = '';
    
    if(preg_match_all('/<img.+src=['"]([^'"]+)['"].*>/i', $post->post_content, $matches)){
        $first_image = $matches [1] [0];
    }

    if (strpos($first_image,$_SERVER['HTTP_HOST'])===false)
    {
            
        //Fetch and Store the Image 
        $get = wp_remote_get( $first_image );
        $type = wp_remote_retrieve_header( $get, 'content-type' );
        $mirror = wp_upload_bits(rawurldecode(basename( $first_image )), '', wp_remote_retrieve_body( $get ) );
    
        //Attachment options
        $attachment = array(
        'post_title'=> basename( $first_image ),
        'post_mime_type' => $type
        );
        
        // Add the image to your media library and set as featured image
        $attach_id = wp_insert_attachment( $attachment, $mirror['file'], $post_ID );
        $attach_data = wp_generate_attachment_metadata( $attach_id, $first_image );
        wp_update_attachment_metadata( $attach_id, $attach_data );
        set_post_thumbnail( $post_ID, $attach_id );
    
        $updated = str_replace($first_image, $mirror['url'], $post->post_content);
        
        //Replace the image in the post
        wp_update_post(array('ID' => $post_ID, 'post_content' => $updated));
    
        // re-hook this function
        add_action('publish_post', 'fetch_images');     
    }
}

Can anyone help fix the the code to make it work with the image tag that I provided? It doesn’t seem to work if the image tag ends with referrerpolicy="no-referrer"