Multiple attachments not working?

I am trying to use the plugin to assign the same image to multiple posts, as the posts are almost a straight copy and paste duplicate of one another each week.

From what I saw, I went into the media library, and I am able to click on the image in question to assign to multiple existing posts. I have done so. However, the thumbnail pull on the pages is not seeing this image.

So I have two questions:

1. Am I doing the process incorrectly? If so, what steps should I be taking instead?

and 2. For future posts will the image automatically be added, or would I have to go and add it every time?

http://wordpress.org/plugins/file-un-attach/