Index: wp-admin/includes/image-edit.php
===================================================================
--- wp-admin/includes/image-edit.php	(revision 23183)
+++ wp-admin/includes/image-edit.php	(working copy)
@@ -692,7 +692,7 @@
 			$_sizes[ $size ] = array( 'width' => get_option("{$size}_size_w"), 'height' => get_option("{$size}_size_h"), 'crop' => $crop );
 		}
 
-		$meta['sizes'] = $img->multi_resize( $_sizes );
+		$meta['sizes'] = array_merge( $meta['sizes'], $img->multi_resize( $_sizes ) );
 	}
 
 	unset( $img );