I recognize that uploads in browser are historically a pain: no progress bars, the lack of ability to do bulk uploads or entire directory uploads are some of the biggest issues. However, recently I've stumbled upon a reasonable solution for this, and one that could be fairly easily added to zen photo: using flash to upload. Google has a great one off the shelf:
http://code.google.com/p/swfupload/
Any thought to having this as an option? I'd love to give zen photo to my clients on their sites, but having a 1:1 image file to file input is maddening. FTP (or zipping files up as an upload, which a lot of other galleries do) don't suffer from this issue, but also require the users to be more tech savy. Any thoughts? I haven't spent a lot of time looking at the plugin api, but could this be a plugin?