[WordPress Plugin] Automatic Post Thumbnail at SANIsoft: "This image can then be easily shown in your blog using a simple function. Mark Jaquith has written an excellent blog post explaining this new feature in detail, do read it if you are wondering how to get started or why post thumbnail widget does not show up in your admin section.
The current implementation of this post thumbnails feature has a few lacunae, the foremost being you have to assign this image manually to the post. So, for your thousands of posts that you created prior to WordPress 2.9 you will end up assigning an image to every post"
'via Blog this'