According to CBSnews:
Why would they delete the image right after someone is cleared? The same lack of logic that caused them to go to scanners instead of using other ways to (like thinking human beings instead of machines) to stop terrorists causes them to say they delete the images right away.
"The (body image scanning) technology is sent to the airports without the ability to save, transmit or print the images," said Greg Soule, TSA spokesman, in an interview with CBSNews.com. "At airports, the images are examined by a security officer in a remote location, and, once the image is cleared, they're deleted."[emphasis added]
If I were going to the trouble to take images of every passenger, I'd at least save them until the flight landed safely. Suppose they delete the images, and a plane explodes and goes down. Wouldn't you want to go through the images to find out what you missed? I sure would.
And CBS' report goes on to discuss the 100 images from a Florida Federal Courthouse that have gone public, which you can see at Gizmodo.
And anyone with a computer knows it can do things you didn't intend. And anyone who knows a human being, knows they don't always do what they're told.
Previous posts on this topic:
1. Updating Havel's "Power of the Powerless" for Airline Pilots
2. Creating Child Porn to Stop Terrorists