That's not a problem. You simply can't select a custom thumbnail for external links for obvious reasons.
Link posts can only contain one link in the URL field. It is superseded by an image you add at the bottom.
If you want to add images, submit them with pic8 (website or sidebar widget) or any other image hosting of your choice and paste the short links in the post content.
Thanks I will try what you suggested.
(post is archived)