I am surprised that the CM attached such weight to the deletion of photographs - a rather common and routine practice. Having seen the poor quality and blurry mess of the images taken they are not pictures you would normally keep.
If the pilot wanted to impede the investigation he could have thrown the memory card and camera away. As I understand it he handed everything over when asked to do so and readily admitted to use of the camera on many sorties.
Still, if he feels that the sentence is overly harsh he can appeal, so the next move his to make.