Tying image thumbnails to posts

I want to be able to attach an image to a post in 2.6, or at least select an image from my image library, put the post in a variable, and be able to pull the image link out of the post and put it in a variable when it’s posted.

Any suggestions? Basically I only want this because at the bottom of my page, I’m going to link to older posts by a little text excerpt, and I want to have a thumbnail used in the post that represents them.