Featured Image Column in Post List

November 17, 2021

This affects all post types. Wrap in conditions to reduce appearance. Featured Image column will appear last.

function add_thumbnail_to_post_list_data($column,$post_id)
{
    switch ($column)
    {
        case 'post_thumbnail':
            echo '<a href="' . get_edit_post_link() . '">'.the_post_thumbnail( 'thumbnail' ).'</a>';
            break;
    }
}
function add_thumbnail_to_post_list( $columns )
{
    $columns['post_thumbnail'] = 'Featured Image';
    return $columns;
}
 
if (function_exists('add_theme_support'))
{
    // Add To Posts
    add_filter( 'manage_posts_columns' , 'add_thumbnail_to_post_list' );
    add_action( 'manage_posts_custom_column' , 'add_thumbnail_to_post_list_data', 10, 2 );
 
    // Add To Pages
    add_filter( 'manage_pages_columns' , 'add_thumbnail_to_post_list' );
    add_action( 'manage_pages_custom_column' , 'add_thumbnail_to_post_list_data', 10, 2 );
}

Reorder Featured Image to be first column:

function add_thumbnail_to_post_list( $columns )
{
    //$columns['post_thumbnail'] = 'Thumbnail';
    
    $columns = array_slice($columns, 0, 1, true) + array("post_thumbnail" => "Featured Image") + array_slice($columns, 1, count($columns) - 1, true);
    return $columns;
}

Style:

add_action('admin_head', 'my_column_width');

function my_column_width() {
    echo '<style type="text/css">';
    echo '.column-mycolumn { text-align: center; width:60px !important; overflow:hidden }';
    echo '</style>';
}

Source – setup with working image.

Source – ordering.

Source – style.

Additional information.