I want to ask: how setup the forum, for the guest not see picture.
Only the members of the forum to see pictures, guest not.

You can't make guests not to see the pictures but you can make them not able to see the topics or not to be able to read what it says in the topics.To do that go to admin panel=>Forum=>Permissions=>Forum Permissions control. From there choose the topic/topics you don't want guests to see by clicking on them and for guests unselect view the forum(if you don't want them to view that topic) and/or Read the topics(so that they won't be able to read the that topic.

Ok, I know that.