I first heard about Webthumb a few weeks ago and thought at the time what a brilliant tool it was. Since then I've been looking forward to playing with the rendering engine it uses. Thankfully it has now been released which I'm pleased about. Webthumb basically takes a snapshot of a site and allows you to download the image as a jpeg. Useful if you want to comment on the design of a site or save an image for future reference. It could also be a useful feature for link directories and the like.
Having said that the web interface is not the best approach to use if you intend to take a screenshot of every site in even a moderately sized link directory. The release of the rendering engine is therefore a welcome development. Released so far is just the rendering engine, not the code that takes the produced image and displays it on the website. If I remember correctly he is not intending to release that code but I can't find where he says that so I may be wrong.
Your correct that im not going to release the webthumb site. But you can easily use PagePrint to make your own script. ./PagePrint -s http://blog.joshuaeichorn.com /tmp/basefile is all you need to take a snapshot.
I'm also planning on releasing an API for webthumb which will allow you to make that whole page of thumbnails without having to install or setup a thing.