diff --git a/wp-content/themes/twentyfourteen/functions.php b/wp-content/themes/twentyfourteen/functions.php
index 51e1b48e26..41f179a457 100644
--- a/wp-content/themes/twentyfourteen/functions.php
+++ b/wp-content/themes/twentyfourteen/functions.php
@@ -461,7 +461,7 @@ add_filter( 'body_class', 'twentyfourteen_body_classes' );
  * @return array The filtered post class list.
  */
 function twentyfourteen_post_classes( $classes ) {
-	if ( ! post_password_required() && has_post_thumbnail() ) {
+	if ( ! post_password_required() && ! is_attachment() && has_post_thumbnail() ) {
 		$classes[] = 'has-post-thumbnail';
 	}
 
diff --git a/wp-content/themes/twentyfourteen/inc/template-tags.php b/wp-content/themes/twentyfourteen/inc/template-tags.php
index dee499e1e2..c911e2a186 100644
--- a/wp-content/themes/twentyfourteen/inc/template-tags.php
+++ b/wp-content/themes/twentyfourteen/inc/template-tags.php
@@ -175,7 +175,7 @@ add_action( 'save_post',     'twentyfourteen_category_transient_flusher' );
  * @return void
 */
 function twentyfourteen_post_thumbnail() {
-	if ( post_password_required() || ! has_post_thumbnail() ) {
+	if ( post_password_required() || is_attachment() || ! has_post_thumbnail() ) {
 		return;
 	}