Supposedly they're not capable of saving or transmitting the pictures. I mean, obviously the machines are capable. But they're nerfed for TSA use. Supposedly.
This is the most ridiculous concept in the digital age. If it's being recorded by a computer, it can be copied. Hell, if it can be seen, it can be illicitly recorded. When you can buy tiny cameras from ThinkGeek that fit in the bridge of your glasses and can record VGA video for hours on a single battery charge, you can forget about pictures not being "saved".
And when the job is looking at naked pictures all day, what do you expect? I mean, who do you think seriously is seeking that sort of job in the first place?