the_post_thumbnail( string|int[] $size = 'post-thumbnail', string|array $attr = '' )
- Since
- 2.9.0
- Source
wp-includes/post-thumbnail-template.php:91
Description
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.
When using the_post_thumbnail() or related functions, the 'post-thumbnail' image size is used by default, though a different size can be specified instead as needed.
Compatibility
- WordPress
- since 2.9.0
- PHP
- 7.4–8.6-dev
- 6.7.7
- 6.8.8
- 6.9.7
- 7.0.4
- 7.1.0
Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.
Parameters
$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:
''
Performance profile
How much work a call to 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
- Scaling
- Constant
- Instructions
- 9
- Plugin surface
- None
- Called by
- 5
Reaches the database via get_post().
No loop in the body: the same number of instructions runs whatever you pass in.
Executed per call on PHP 8.5. The body compiles to 9.
Nothing here hands control to plugin code.
5 places in core call this, so the cost is paid more often than your own code shows.
What it touches
- querycontent query
get_post()one call below the_post_thumbnail() - hookthird-party callbacks
apply_filters()one call below the_post_thumbnail()
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 · 1 distinct outcome
One number would be a lie: the work depends on which branch runs. These are every distinct cost the_post_thumbnail() can have, taken from its control-flow graph on PHP 8.5.
| When | Instructions | Calls it makes |
|---|---|---|
| always | 9 | get_the_post_thumbnail() |
Across PHP versions
Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 9 instructions, 9 executed per call, 0 branches. The work does not change between versions.
An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.
Uses · 1
- get_the_post_thumbnail()Retrieves the post thumbnail.
Used by · 5
- twenty_twenty_one_post_thumbnail()Displays an optional post thumbnail.
- twentyfifteen_post_thumbnail()Display an optional post thumbnail.
- twentyfourteen_post_thumbnail()Display an optional post thumbnail.
- twentynineteen_post_thumbnail()Displays an optional post thumbnail.
- twentysixteen_post_thumbnail()Displays an optional post thumbnail.
Source code
function the_post_thumbnail( $size = 'post-thumbnail', $attr = '' ) { echo get_the_post_thumbnail( null, $size, $attr );}Changelog
Introduced in 2.9.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
About this page
- Parsed data
- Generated from the wordpress-develop 6.7.7 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
- Something wrong on this page? Report it and it gets fixed in the next regeneration.