A couple of questions after installing zenphoto. First, I'm using the Stop Design theme, and when I set the thumbnails to be a new size (250px ch225 cw225), it just seems to fit the old thumbnail size in the new box. I rebuilt the cache, I deleted the cache folder, nothing works, it just keeps building 100 size thumbnails.

Second, I need to display these in a slide show, just a link somewhere on the theme. I can handle the link, but is slide show functionality built-in?

You are right, this is a problem with 1.1. You can download a fixed version from the nightly build here: http://www.zenphoto.org/files/nightly/

Version 1.1.1 will be out within a day or two.

There is no slideshow built in to zenphoto.