diff --git a/src/wp-includes/media.php b/src/wp-includes/media.php
index 19c6ffa38a..c8bb9167f6 100644
--- a/src/wp-includes/media.php
+++ b/src/wp-includes/media.php
@@ -822,8 +822,8 @@ function wp_get_attachment_image($attachment_id, $size = 'thumbnail', $icon = fa
  * @since 4.4.0
  *
  * @param int          $attachment_id Image attachment ID.
- * @param string|array $size          Optional. Registered image size to retrieve the source for or a flat
- *                                    array of height and width dimensions. Default 'thumbnail'.
+ * @param string|array $size          Optional. Image size to retrieve. Accepts any valid image size, or an array
+ *                                    of width and height values in pixels (in that order). Default 'thumbnail'.
  * @param bool         $icon          Optional. Whether the image should be treated as an icon. Default false.
  * @return string|false Attachment URL or false if no image is available.
  */