Add Post Featured Thumbnail To Post List on WordPress

Adding a featured image for each post is important for your website’s beauty & very much for the SEO part.

To make sure all posts have a featured image, use this code to add a thumbnail of the image to the post list in your wp-admin:

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'] = 'Thumbnail';
    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 );
}