I just got the plugin “post_avatar” and it works great with WP 2.1. I think this is what you are looking for, at least I hope it is.
From the readme file.
== FEATURES ==
* Easy selection of images in the Write Post screen.
* Scans images in sub-directories of the image option folder.
* Allows the following file types: .jpg, .jpeg, .gif and .png.
* Avatars show up automatically or use a template tag to customize display in themes.
* Does not display missing images.
