"But Mr. Donahoe said that the images had been used “a couple of times” by law enforcement to trace letters in criminal cases, including one involving ricin-laced letters sent to President Obama and Mayor Michael R. Bloomberg of New York. The images of letters and packages are generally stored for a week to 30 days and then destroyed, he told the A.P."
[end of quote from article]
About that article.
I think it's curious that they claim to "destroy' the images after "a week to 30 days". If there are about 1 billion mailed items each year, and it takes 50 kilobytes to store an image (wild ass guess, and assuming some compression), that would amount to 50 terabytes of data: A bit more than 4 of the largest-capacity of hard drives currently sold.