I have been having this problem for the last two days on all the computers in my house so I know it's not a set-up problem at my end. I click on a thumbnail and I get a message saying I don't have permission to look at the picture, but when I try to log in again on that page it won't let me in.
Could we possibly have a system where anyone can see the photo's but you see a watermark if you're not a member of the site to prevent people's photo's being stolen?