Looks like a good start. I suspect that uploading zip files is not needed, but the new album feature would be nice.
I notice that there are considerable chagnes to the `jquery.fileupload.js` script. I wonder if you might consider offering these up to the jQuery File upload plugin project https://github.com/blueimp/jQuery-File-Upload . We try hard not to make modifications to third party scripts (for the same reason we suggest people take the tact you used and make a new set of scripts to modify.)
If your changes were incorporated in that project it would make things much simpler in the long run. (I also notice while checking this that they have a newer version we will have to deal with at some point. It would be really cool if you managed to both get your changes incorporated and migrate the zenphoto plugin to the resulting version!)
Anyway, good work.