Algorithm spots forgeries by spotting shadows that don't match light sources. (ISNS) -- A new algorithm can spot fake photos by looking for inconsistent shadows that are not always obvious to the naked eye. The technique, which will be published in the journal ACM Transactions on Graphics in September, is the latest tool in the increasingly sophisticated arms race between digital forensics experts and those who manipulate photos or create fake tableaus for deceptive purposes. National security agencies, the media, scientific journals and others use digital forensic techniques to differentiate between authentic images and computerized forgeries. James O'Brien, a computer...