I too am not optimistic about the ability of a jury to comprehend a technical argument. However, in this instance I believe the defense has the greatest comeback of all time: hand the expert a similar phone with a series of pictures on it and ask him to show how it is done without leaving a trace. Either it is easy to do - that is a bunch of college kids can do it - or it cannot be done without leaving a trace.
Sorry: The expert could definitely be a he or a she.
I tend to agree. I think juries will tend to believe photographs are not altered unless someone can convincingly show they they are altered.
Now as for a judge not admitting them into evidence, I don't know. I am a little surprised by Locomotive Breath's argument. It is not like regular photographs can not be altered. I would think it might depend on which side it trying to introduce the evidence. Remember a defendent need only create doubt.
It would to me hard to argue that a defendant may not introduce photographic evidence unless it can be shown to be altered. But then I am not an attorney nor a judge, just merely an economist who thinks implicit in the US Constitution is that a defendant can offer whatever defense he wants.