--- a/web/wp-includes/post-thumbnail-template.php	Thu Sep 16 15:45:36 2010 +0000
+++ b/web/wp-includes/post-thumbnail-template.php	Mon Nov 19 18:26:13 2012 +0100
@@ -11,60 +11,85 @@
 
 /**
  * Check if post has an image attached.
- * 
+ *
  * @since 2.9.0
  *
  * @param int $post_id Optional. Post ID.
- * @return bool Whether post has an image attached (true) or not (false).
+ * @return bool Whether post has an image attached.
  */
-function has_post_thumbnail( $post_id = NULL ) {
-	global $id;
-	$post_id = ( NULL === $post_id ) ? $id : $post_id;
-	return !! get_post_thumbnail_id( $post_id );
+function has_post_thumbnail( $post_id = null ) {
+	return (bool) get_post_thumbnail_id( $post_id );
 }
 
 /**
  * Retrieve Post Thumbnail ID.
- * 
+ *
  * @since 2.9.0
  *
  * @param int $post_id Optional. Post ID.
  * @return int
  */
-function get_post_thumbnail_id( $post_id = NULL ) {
-	global $id;
-	$post_id = ( NULL === $post_id ) ? $id : $post_id;
+function get_post_thumbnail_id( $post_id = null ) {
+	$post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
 	return get_post_meta( $post_id, '_thumbnail_id', true );
 }
 
 /**
  * Display Post Thumbnail.
- * 
+ *
  * @since 2.9.0
  *
- * @param int $size Optional. Image size.  Defaults to 'post-thumbnail', which theme sets using set_post_thumbnail_size( $width, $height, $crop_flag );.
+ * @param int $size Optional. Image size. Defaults to 'post-thumbnail', which theme sets using set_post_thumbnail_size( $width, $height, $crop_flag );.
  * @param string|array $attr Optional. Query string or array of attributes.
  */
 function the_post_thumbnail( $size = 'post-thumbnail', $attr = '' ) {
-	echo get_the_post_thumbnail( NULL, $size, $attr );
+	echo get_the_post_thumbnail( null, $size, $attr );
+}
+
+/**
+ * Update cache for thumbnails in the current loop
+ *
+ * @since 3.2
+ *
+ * @param object $wp_query Optional. A WP_Query instance. Defaults to the $wp_query global.
+ */
+function update_post_thumbnail_cache( $wp_query = null ) {
+	if ( ! $wp_query )
+		$wp_query = $GLOBALS['wp_query'];
+
+	if ( $wp_query->thumbnails_cached )
+		return;
+
+	$thumb_ids = array();
+	foreach ( $wp_query->posts as $post ) {
+		if ( $id = get_post_thumbnail_id( $post->ID ) )
+			$thumb_ids[] = $id;
+	}
+
+	if ( ! empty ( $thumb_ids ) ) {
+		_prime_post_caches( $thumb_ids, false, true );
+	}
+
+	$wp_query->thumbnails_cached = true;
 }
 
 /**
  * Retrieve Post Thumbnail.
- * 
+ *
  * @since 2.9.0
  *
  * @param int $post_id Optional. Post ID.
- * @param string $size Optional. Image size.  Defaults to 'thumbnail'.
+ * @param string $size Optional. Image size. Defaults to 'post-thumbnail'.
  * @param string|array $attr Optional. Query string or array of attributes.
-  */
-function get_the_post_thumbnail( $post_id = NULL, $size = 'post-thumbnail', $attr = '' ) {
-	global $id;
-	$post_id = ( NULL === $post_id ) ? $id : $post_id;
+ */
+function get_the_post_thumbnail( $post_id = null, $size = 'post-thumbnail', $attr = '' ) {
+	$post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
 	$post_thumbnail_id = get_post_thumbnail_id( $post_id );
 	$size = apply_filters( 'post_thumbnail_size', $size );
 	if ( $post_thumbnail_id ) {
 		do_action( 'begin_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size ); // for "Just In Time" filtering of all of wp_get_attachment_image()'s filters
+		if ( in_the_loop() )
+			update_post_thumbnail_cache();
 		$html = wp_get_attachment_image( $post_thumbnail_id, $size, false, $attr );
 		do_action( 'end_fetch_post_thumbnail_html', $post_id, $post_thumbnail_id, $size );
 	} else {
@@ -72,5 +97,3 @@
 	}
 	return apply_filters( 'post_thumbnail_html', $html, $post_id, $post_thumbnail_id, $size, $attr );
 }
-
-?>
\ No newline at end of file