Seems like the images are hotlink-protcted (you can check them here:
Test hotlink protection - Htaccess Tools) so they can not be uploaded to your host. That means that met-art and ftv do not want you to promote their content at your site.
P.S. This is an offtopic, but if I were you I would never touch sites like met-art even with a long stick... Read this:
https://wikileaks.org/wiki/An_insight_into_child_porn and use Ctrl+S to spot the site name there.