I had the same problem just recently, I posted 3 pics on the forum 2 were correct one needed rotating. I tried rotating the picture in the original computer file , but it made no difference . The only conclusion I could come to was that 2 of the pics were taken with the camera in landscape position ( these were fine) and one taken with camera in portrait position this needed rotating , why this made a difference I have no idea. I would also welcome some info.
