- $old_content_width = $content_width;
- $content_width = 266;
- if ( !isset( $_wp_additional_image_sizes['post-thumbnail'] ) )
- $thumbnail_html = wp_get_attachment_image( $thumbnail_id, array( $content_width, $content_width ) );
- else
- $thumbnail_html = wp_get_attachment_image( $thumbnail_id, 'post-thumbnail' );
- if ( !empty( $thumbnail_html ) ) {
- $ajax_nonce = wp_create_nonce( 'set_post_thumbnail-' . $post->ID );
- $content = sprintf( $set_thumbnail_link, $upload_iframe_src, $thumbnail_html );
- $content .= '<p class="hide-if-no-js"><a href="#" id="remove-post-thumbnail" onclick="WPRemoveThumbnail(\'' . $ajax_nonce . '\');return false;">' . esc_html__( 'Remove featured image' ) . '</a></p>';
+ $size = isset( $_wp_additional_image_sizes['post-thumbnail'] ) ? 'post-thumbnail' : array( 266, 266 );
+
+ /**
+ * Filters the size used to display the post thumbnail image in the 'Featured Image' meta box.
+ *
+ * Note: When a theme adds 'post-thumbnail' support, a special 'post-thumbnail'
+ * image size is registered, which differs from the 'thumbnail' image size
+ * managed via the Settings > Media screen. See the `$size` parameter description
+ * for more information on default values.
+ *
+ * @since 4.4.0
+ *
+ * @param string|array $size Post thumbnail image size to display in the meta box. Accepts any valid
+ * image size, or an array of width and height values in pixels (in that order).
+ * If the 'post-thumbnail' size is set, default is 'post-thumbnail'. Otherwise,
+ * default is an array with 266 as both the height and width values.
+ * @param int $thumbnail_id Post thumbnail attachment ID.
+ * @param WP_Post $post The post object associated with the thumbnail.
+ */
+ $size = apply_filters( 'admin_post_thumbnail_size', $size, $thumbnail_id, $post );
+
+ $thumbnail_html = wp_get_attachment_image( $thumbnail_id, $size );
+
+ if ( ! empty( $thumbnail_html ) ) {
+ $content = sprintf( $set_thumbnail_link,
+ esc_url( $upload_iframe_src ),
+ ' aria-describedby="set-post-thumbnail-desc"',
+ $thumbnail_html
+ );
+ $content .= '<p class="hide-if-no-js howto" id="set-post-thumbnail-desc">' . __( 'Click the image to edit or update' ) . '</p>';
+ $content .= '<p class="hide-if-no-js"><a href="#" id="remove-post-thumbnail">' . esc_html( $post_type_object->labels->remove_featured_image ) . '</a></p>';