Ajouter l’image à la une dans une colonne de la liste de posts.

                    <?php 
function undfnd_posts_custom_column( $column, $post_id ) {
    if( $column == 'img' ) {
        echo get_the_post_thumbnail($post_id, 'thumbnail', [ 'style' => 'max-width: 80px; height: auto;' ]);
    }
    return $column;
}
add_action( 'manage_posts_custom_column', 'undfnd_posts_custom_column', 10, 2);
function undfnd_manage_posts_columns( $columns ) {
    $columns['img'] = 'Featured Image';
    return $columns;
}
add_filter( 'manage_posts_custom_column', 'undfnd_manage_posts_columns');