Linking a post??????? Helppp!!!!

Hello

I want with a click in a image go to a certain post but I reed in the codex this:

Linking options: With this option you will be able to change the linking properties of the file. The options are:

* Linked to file: The link sent to Post Editor will be the file itself
* Linked to page: The link sent to Post Editor will go to a special page, where you will see the title an description saved with the file

It seem that I only can do this with a page. It’s possible with a post, how???????? Any help is appreciate thanks in advance.