add check to make sure image has an owner before rendering the owner

app/views/admin/image/index.pug

@@ -33,11 +33,12 @@ block content
                       span
                         i.fas.fa-trash
                       span.uk-margin-small-left Delete image
-                  li
-                    a(href=`/admin/image/${image._id}/archive-user`).uk-text-truncate
-                      span
-                        i.fas.fa-file-archive
-                      span.uk-margin-small-left Archive and ban #[span.uk-text-bold= image.owner.username]
+                  if image.owner
+                    li
+                      a(href=`/admin/image/${image._id}/archive-user`).uk-text-truncate
+                        span
+                          i.fas.fa-file-archive
+                        span.uk-margin-small-left Archive and ban #[span.uk-text-bold= image.owner.username]
 
     +renderPaginationBar('/admin/image', images.totalImageCount)