This is a poorly written article by a fairly dumb reporter.
There really are dogs who can pick up the scent of a flash drive (not the presence of porn, but the presence of a binding agent used to make the flash drive). This is how they found stuff in Jared Fogle’s home.
The reporter is just dumb and doesn’t understand.
And it makes sense. People who want to hide or trade child pornography would be likely to use a flash drive.