diff --git a/wp-admin/includes/image-edit.php b/wp-admin/includes/image-edit.php
index cdb1cf8e98..f8a9d507f7 100644
--- a/wp-admin/includes/image-edit.php
+++ b/wp-admin/includes/image-edit.php
@@ -567,7 +567,7 @@ function stream_preview_image( $post_id ) {
 function wp_restore_image($post_id) {
 	$meta = wp_get_attachment_metadata($post_id);
 	$file = get_attached_file($post_id);
-	$backup_sizes = get_post_meta( $post_id, '_wp_attachment_backup_sizes', true );
+	$backup_sizes = $old_backup_sizes = get_post_meta( $post_id, '_wp_attachment_backup_sizes', true );
 	$restored = false;
 	$msg = new stdClass;
 
@@ -629,7 +629,9 @@ function wp_restore_image($post_id) {
 		}
 	}
 
-	if ( !wp_update_attachment_metadata($post_id, $meta) || !update_post_meta( $post_id, '_wp_attachment_backup_sizes', $backup_sizes) ) {
+	if ( ! wp_update_attachment_metadata( $post_id, $meta ) ||
+		( $old_backup_sizes !== $backup_sizes && ! update_post_meta( $post_id, '_wp_attachment_backup_sizes', $backup_sizes ) ) ) {
+
 		$msg->error = __('Cannot save image metadata.');
 		return $msg;
 	}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index a61d23176a..07c5836780 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31069';
+$wp_version = '4.2-alpha-31070';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.