Force Featured Image

インストール

1. Upload force-featured-image to the /wp-content/plugins/ directory
2. Activate the plugin through the ‘Plugins’ menu in WordPress

3. This plugin lets you specify which post-type requires to force a featured image to. It will also let you specify minimum dimensions for the image.
   Let’s say, for example, you want to force a user to set an image on the default post type with the following dimensions (400px * 400px). Put this code in the function.php of your theme :

   function theme_force_featured_image( $options ){
       $options['post'] = array(
           'width'  => 400,
           'height' => 400,
       );
   
       return $options;
   }
   add_filter( 'force_featured_image_post_type', 'theme_force_featured_image' );