Thank you for posting this. I want to do almost exactly this, and set up another task running that will zip up all the images and send them off to my referee.

Unfortunately, I haven't gotten this to work. I'm not very familiar with cron, and I don't know how to debug it. My script works as intended when run manually, but halts (dies? I don't know) when run from cron (at import). I haven't managed to get any error reporting, either by redirecting the script output or the import output. I also haven't been able to get import to run directly from cron, even by using absolute paths and no variables. I suspect these are problems you haven't run across, but if you have, I'd appreciate your advice.