get_post_thumbnail_id( int|WP_Post $post = null )

Retrieve post thumbnail ID.

Parameters

$post

(int|WP_Post) (Optional) Post ID or WP_Post object. Default is global $post.

Default value: null

Return

(int|false) Post thumbnail ID (which can be 0 if the thumbnail is not set), or false if the post does not exist.

More Information

  • To enable featured images, see post thumbnails, the current theme must include add_theme_support( 'post-thumbnails' ); in its functions.php file. See also Post Thumbnails.
  • “Post Thumbnail” is an outdated term for “Featured Image”. This function returns the ID of the post’s featured image. It does not return IDs of other images attached to posts that are thumbnail sized.

Source

File: wp-includes/post-thumbnail-template.php 

function get_post_thumbnail_id( $post = null ) {
	$post = get_post( $post );

	if ( ! $post ) {
		return false;
	}

	return (int) get_post_meta( $post->ID, '_thumbnail_id', true );
}

Uses

Uses Description
wp-includes/post.php: get_post_meta()

Retrieves a post meta field for the given post ID.
wp-includes/post.php: get_post()

Retrieves post data given a post ID or post object.

Used By

Used By Description
wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php: WP_REST_Posts_Controller::prepare_links()

Prepares links for the request.
wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php: WP_REST_Posts_Controller::prepare_item_for_response()

Prepares a single post output for response.
wp-includes/post-thumbnail-template.php: get_the_post_thumbnail_caption()

Returns the post thumbnail caption.
wp-includes/embed.php: get_oembed_response_data_rich()

Filters the oEmbed response data to return an iframe embed code.
wp-includes/post-thumbnail-template.php: get_the_post_thumbnail_url()

Return the post thumbnail URL.
wp-admin/includes/media.php: edit_form_image_editor()

Displays the image and editor in the post editor
wp-admin/includes/media.php: get_media_item()

Retrieve HTML form for modifying the image attachment.
wp-includes/post-thumbnail-template.php: has_post_thumbnail()

Determines whether a post has an image attached.
wp-includes/post-thumbnail-template.php: update_post_thumbnail_cache()

Update cache for thumbnails in the current loop.
wp-includes/post-thumbnail-template.php: get_the_post_thumbnail()

Retrieve the post thumbnail.
wp-includes/post-template.php: prepend_attachment()

Wrap attachment in paragraph tag before content.
wp-includes/media.php: wp_prepare_attachment_for_js()

Prepares an attachment post object for JS, where it is expected to be JSON-encoded and fit into an Attachment model.
wp-includes/media.php: wp_playlist_shortcode()

Builds the Playlist shortcode output.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mw_getPost()

Retrieve post.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::mw_getRecentPosts()

Retrieve list of recent posts.
wp-includes/class-wp-xmlrpc-server.php: wp_xmlrpc_server::_prepare_post()

Prepares post data for return in an XML-RPC object.

Changelog

Version Description
5.5.0 The return value for a non-existing post was changed to false instead of an empty string.
4.4.0 $post can be a post ID or WP_Post object.
2.9.0 Introduced.

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Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/get_post_thumbnail_id