Index: src/wp-includes/media.php
===================================================================
--- src/wp-includes/media.php	(revision 31227)
+++ src/wp-includes/media.php	(working copy)
@@ -2639,7 +2639,7 @@
 		'type'        => $type,
 		'subtype'     => $subtype,
 		'icon'        => wp_mime_type_icon( $attachment->ID ),
-		'dateFormatted' => mysql2date( get_option('date_format'), $attachment->post_date ),
+		'dateFormatted' => mysql2date( __( 'F j, Y' ), $attachment->post_date ),
 		'nonces'      => array(
 			'update' => false,
 			'delete' => false,