Index: src/wp-admin/includes/media.php
===================================================================
--- src/wp-admin/includes/media.php	(revision 49793)
+++ src/wp-admin/includes/media.php	(working copy)
@@ -3288,7 +3288,7 @@
 
 	$att_url = wp_get_attachment_url( $attachment_id );
 
-	$author = get_userdata( $post->post_author );
+	$author = new WP_User( $post->post_author );
 
 	$uploaded_by_name = __( '(no author)' );
 	$uploaded_by_link = '';