Order post by thumbnail (featured image) presence.

function posts_columns($defaults){
    $defaults['riv_post_thumbs'] = __('Thumbs');
    return $defaults;
}

function posts_custom_columns($column_name, $id){
    if($column_name === 'riv_post_thumbs'){
        echo the_post_thumbnail( array(70,70) );
    }
}


function korleon_nothumb_first($query){

    if( !is_admin()
        || !$query->is_main_query()
        || !$query->query['post_type']==='post'
        || !( isset($_GET['orderby']) &&  $_GET['orderby']==='riv_post_thumbs' )
        || !isset($_GET['order'])
    ) return;

    $order = ( $_GET['order']==='asc' ) ? 'ASC' : 'DESC';

    $query->set('meta_query',array(

        'relation' => 'OR',


            array(
                'key'     => '_thumbnail_id',
                'compare' => 'NOT EXISTS',
                'value' => ''
            ),


            array(
                'key'     => '_thumbnail_id',
                'compare' => 'EXISTS',

            )

    ));

    $query->set('orderby','meta_value_num');
    $query->set('order', $order );

}

add_filter('manage_posts_columns', 'posts_columns', 5);
add_action('manage_posts_custom_column', 'posts_custom_columns', 5, 2);

add_filter('pre_get_posts', 'korleon_nothumb_first', 999);

// edit-post

add_filter('manage_edit-post_sortable_columns', 'sort_thumb');

function sort_thumb($sortable){

    $sortable['riv_post_thumbs'] = 'riv_post_thumbs';
    return $sortable;

}