Chain of evidance?

If he has a good lawyer he could equally argue that the best buy tech's had ample time with the machine to put the pictures on and falsify logs. It's very hard to provide an uncorrupted chain of evidence with PC's.

Lawyer: So how did you discover the pictures were on the laptop?

Tech: I turned it on.

Lawyer: No more questions your honour.

Expert witness: The boot process has altered the contents of the hard disk.

Lawyer: The evidence has been tampered with, I move that exhibit A is inadmissible.

The judge will most likely not be failure with how computers work but he will know how evidence works and have to drop it.