My guess is something wrong with your pictures or the phone your using is causing the issue? Have you tried to add a picture on a computer or different device.
Internet connection could cause it. try a different connection. clear the cookies on your device. Waiting will most likely do nothing as no one else seems to have the problem.
Good luck
You need to either add a week (do that up at the top next to the list of weeks)
or edit a week (select that button right above the photos)
Did you contact tech support?