I completely forgot to setup the email settings on the Demo Site 3 when I set it but as of today you can register and get the email needed to confirm registration and start posting on that site, with editor privleges.
That means you can upload images to the Library and create posts. So give it a try. I will leave it active for at least 3 more days.
Follow Tim on Twitter @tl1000rzx2
Or check out my other blog: THE Tablet Test Server