get_the_post_thumbnail( int|WP_Post|null $post = null, string|int[] $size = 'post-thumbnail', string|array $attr = '' ): string

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$postint|WP_Post|nulloptional

Post ID or WP_Post object. Default is global $post.Default: null

$sizestring|int[]optional

Image size. Accepts any registered image size name, or an array of width and height values in pixels (in that order). Default 'post-thumbnail'.Default: 'post-thumbnail'

$attrstring|arrayoptional

Query string or array of attributes. Default empty.Default: ''

Return value

string

The post thumbnail image tag.

Performance profile

How much work a call to get_the_post_thumbnail() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Heavy

Reaches the database via get_post().

Scaling

Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions

9–61

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 63.

Plugin surface

4 hooks

Third-party callbacks on 'post_thumbnail_size', 'begin_fetch_post_thumbnail_html', 'end_fetch_post_thumbnail_html' run inside this call, and their cost is not bounded by anything here.

Called by

5

5 places in core call this, so the cost is paid more often than your own code shows.

What it touches

• querycontent queryget_post()called directly
• hookthird-party callbacksapply_filters()called directly

Further down the call graph this can also reach cache, serialize, option and transient. Those are the worst case, several calls deep and usually down an error path, not what a normal call pays.

What one call costs · 4 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost get_the_post_thumbnail() can have, taken from its control-flow graph on PHP 8.5.

Hooks and filters fired · 4

4 hooks fire while get_the_post_thumbnail() runs, in this order:

1. 1
   apply_filters( post_thumbnail_size )filterline 184 (+19 into the body)

   Filters the post thumbnail size.

2. 2
   do_action( begin_fetch_post_thumbnail_html )actionline 200 (+35 into the body)

   Fires before fetching the post thumbnail HTML.

3. 3
   do_action( end_fetch_post_thumbnail_html )actionline 218 (+53 into the body)

   Fires after fetching the post thumbnail HTML.

4. 4
   apply_filters( post_thumbnail_html )filterline 236 (+71 into the body)

   Filters the post thumbnail HTML.

Uses · 7

• get_post()Retrieves post data given a post ID or post object.
• get_post_thumbnail_id()Retrieves the post thumbnail ID.
• apply_filters()Calls the callback functions that have been added to a filter hook.
• do_action()Calls the callback functions that have been added to an action hook.
• in_the_loop()Determines whether the caller is in the Loop.
• update_post_thumbnail_cache()Updates cache for thumbnails in the current loop.
• wp_get_attachment_image()Gets an HTML img element representing an image attachment.

Used by · 5

• Twenty_Fourteen_Ephemera_Widget::widget()Outputs the HTML for this widget.
• render_block_core_cover()Renders the `core/cover` block on server.
• render_block_core_latest_posts()Renders the `core/latest-posts` block on server.
• render_block_core_post_featured_image()Renders the `core/post-featured-image` block on the server.
• the_post_thumbnail()Displays the post thumbnail.

Source code

View on Trac ↗View on GitHub ↗

165function get_the_post_thumbnail( $post = null, $size = 'post-thumbnail', $attr = '' ) {166	$post = get_post( $post );167 168	if ( ! $post ) {169		return '';170	}171 172	$post_thumbnail_id = get_post_thumbnail_id( $post );173 174	/**175	 * Filters the post thumbnail size.176	 *177	 * @since 2.9.0178	 * @since 4.9.0 Added the `$post_id` parameter.179	 *180	 * @param string|int[] $size    Requested image size. Can be any registered image size name, or181	 *                              an array of width and height values in pixels (in that order).182	 * @param int          $post_id The post ID.183	 */184	$size = apply_filters( 'post_thumbnail_size', $size, $post->ID );185 186	if ( $post_thumbnail_id ) {187 188		/**189		 * Fires before fetching the post thumbnail HTML.190		 *191		 * Provides "just in time" filtering of all filters in wp_get_attachment_image().192		 *193		 * @since 2.9.0194		 *195		 * @param int          $post_id           The post ID.196		 * @param int          $post_thumbnail_id The post thumbnail ID.197		 * @param string|int[] $size              Requested image size. Can be any registered image size name, or198		 *                                        an array of width and height values in pixels (in that order).199		 */200		do_action( 'begin_fetch_post_thumbnail_html', $post->ID, $post_thumbnail_id, $size );201 202		if ( in_the_loop() ) {203			update_post_thumbnail_cache();204		}205 206		$html = wp_get_attachment_image( $post_thumbnail_id, $size, false, $attr );207 208		/**209		 * Fires after fetching the post thumbnail HTML.210		 *211		 * @since 2.9.0212		 *213		 * @param int          $post_id           The post ID.214		 * @param int          $post_thumbnail_id The post thumbnail ID.215		 * @param string|int[] $size              Requested image size. Can be any registered image size name, or216		 *                                        an array of width and height values in pixels (in that order).217		 */218		do_action( 'end_fetch_post_thumbnail_html', $post->ID, $post_thumbnail_id, $size );219 220	} else {221		$html = '';222	}223 224	/**225	 * Filters the post thumbnail HTML.226	 *227	 * @since 2.9.0228	 *229	 * @param string       $html              The post thumbnail HTML.230	 * @param int          $post_id           The post ID.231	 * @param int          $post_thumbnail_id The post thumbnail ID, or 0 if there isn't one.232	 * @param string|int[] $size              Requested image size. Can be any registered image size name, or233	 *                                        an array of width and height values in pixels (in that order).234	 * @param string|array $attr              Query string or array of attributes.235	 */236	return apply_filters( 'post_thumbnail_html', $html, $post->ID, $post_thumbnail_id, $size, $attr );237}

Changelog

Introduced in 2.9.0. One change between 6.7.7 and 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/post-thumbnail-template.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

Corrections

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