I made a new plugin called Post Thumbs to share. It has barely been tested, so if anyone tries it and has some problems hopefully I'll know what's wrong. It works on my site fine.
What it does is scan a post for an included image and convert that image into a thumbnail to be used in The Loop. You could use this to show a list of posts as thumbnail links if you wanted. It will only work for images that reside on your server. No support for cross domain images as of yet.
The documentation is shoddy, but it'll have to do for now. If anyone has any suggestions, feel free to reply. The plugin is here.