Filters the size used to display the post thumbnail image in the ‘Featured image’ meta box.

Note: When a theme adds ‘post-thumbnail’ support, a special ‘post-thumbnail’ image size is registered, which differs from the ‘thumbnail’ image size managed via the Settings > Media screen.

$size string|int[]

Requested image size. Can be any registered image size name, or an array of width and height values in pixels (in that order).

$thumbnail_id int

Post thumbnail attachment ID.

$post WP_Post

The post object associated with the thumbnail.

File: wp-admin/includes/post.php. View all references

$size = apply_filters( 'admin_post_thumbnail_size', $size, $thumbnail_id, $post );