Twenty Twenty-One: Do not specify `loading=“eager”` for single post thumbnails.

While `loading=“eager”` is a supported alternative to omitting the attribute entirely, browsers follow the value of this attribute explicitly when specified.

Specifying `eager` would prevent the user from receiving any additional potential benefits implemented at the browser level, such as further mechanisms to automatically decide which elements to lazy-load.

Props flixos90, ryelle, poena.
Merges [49860] to the 5.6 branch.
Fixes #52139.
Built from https://develop.svn.wordpress.org/branches/5.6@49861


git-svn-id: http://core.svn.wordpress.org/branches/5.6@49580 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-content/themes/twentytwentyone/inc/template-tags.php

@@ -190,8 +190,8 @@ if ( ! function_exists( 'twenty_twenty_one_post_thumbnail' ) ) {
 
 			<figure class="post-thumbnail">
 				<?php
-				// Thumbnail is loaded eagerly because it's going to be in the viewport immediately.
-				the_post_thumbnail( 'post-thumbnail', array( 'loading' => 'eager' ) );
+				// Lazy-loading attributes should be skipped for thumbnails since they are immediately in the viewport.
+				the_post_thumbnail( 'post-thumbnail', array( 'loading' => false ) );
 				?>
 				<?php if ( wp_get_attachment_caption( get_post_thumbnail_id() ) ) : ?>
 					<figcaption class="wp-caption-text"><?php echo wp_kses_post( wp_get_attachment_caption( get_post_thumbnail_id() ) ); ?></figcaption>

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.6.1-alpha-49855';
+$wp_version = '5.6.1-alpha-49861';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.