Thickbox does not work with JQuery 1.3 Beta Release...be warned. If you follow the link to download the "latest" Jquery from the Thickbox page, it won't work on things such as Gallery...you'll just be shown the "loading" graphic forever. Ironic? Yes!
Ok I tried changing that line of code and it fails with just the simple image box. It seems to just load the image in place without overlaying it at all.
I still don't understand what is happening but it has something to do with running this script through my XAMPP server: when files are run through the web server Thickbox breaks yet when I preview the files outside of the XAMPP server environment they work; including my remote server.
Weird issue as other jQuery scripts in the same project run fine and I have no idea why server-side things would affect this. Going to make development a pain in the yang.
I downloaded all the files from the demo/thickbox site on april 1 2009. You download 1.3.2 jquery from the site. The thickbox works fine for 1 image, but when I added the rel attribute it broke. I made the change hannes recommends on line 79 of thickbox.js... works now