Index: wp-includes/post-thumbnail-template.php
===================================================================
--- wp-includes/post-thumbnail-template.php	(revision 23175)
+++ wp-includes/post-thumbnail-template.php	(working copy)
@@ -39,7 +39,7 @@
  *
  * @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 string $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 = '' ) {