I was looking for a solution in the forum but couldn't find it.
Probably it's something related to permissions, I checked Guests permissions are can't find a reason for this problem.
I attach an image, add a link and get this code:
But, a non-registered user see the following:
<a href="http://site.com" target="_blank"><img src="http://site.com/data/attachments/29/29123-bbf60dc00eab2662678815360b355949.jpg" alt="attachment-alt" class="bbCodeImage"></a>
The example is here:
If you need it I can provide a test user.
Thanks for your help!