I have just read that the woman took the photo thinking it could be Maddie, although surely if that were the case she would take the camera straight to local police, not download them three weeks later. All the papers give different reports. The 'Mail's' report (dubious) says that the woman was 99% sure it was Maddie.
Personally, I think the girl looks too young and the hair falls differently with a natural parting on the other side. Although there are a quite a number of fair haired people, especially children, in Morocco.