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function is not described

_wp_post_thumbnail_class_filter_add() WP 2.9.0

Adds '_wp_post_thumbnail_class_filter' callback to the 'wp_get_attachment_image_attributes' filter hook. Internal use only.

This is an internal function for using it by WP core itself. It's not recommended to use this function in your code.

No Hooks.


null. Null. Nothing.


_wp_post_thumbnail_class_filter_add( $attr );
$attr(string[]) (required)
Array of thumbnail attributes including src, class, alt, title, keyed by attribute name.


Since 2.9.0 Introduced.

Code of _wp_post_thumbnail_class_filter_add() WP 5.7

function _wp_post_thumbnail_class_filter_add( $attr ) {
	add_filter( 'wp_get_attachment_image_attributes', '_wp_post_thumbnail_class_filter' );