Can't add photos, or make any other edits. arrowphotos.com
What OS and browser you using?
I used to use Safari and it would drive me nuts logging me out multiple times a day. Switched over to Chrome a while back and I don't think I've had to re-login in months. If it is another browser you're using, the only real solution is to clear all your cookies/browsing data and try again.
For using Safari and a custom domain, please see this post I just made.
I use Chrome and I have already tried removing all my cookies/browsing data. Still have the problem.
leftquark told me to delete 3rd party cookie restriction and that worked. I am all good now.