NEW YORK : The US National Security Agency is, through its global surveillance programme, increasingly gathering electronic images for its facial-recognition programme, according to documents obtained by The New York Times.The spy agency has relied more on facial-recognition technology in the past four years as a result of new software that can process the flood of digital communications such as emails, text messages and even video conferences, according to the documents obtained from former NSA contractor Edward Snowden. NSA officials think the new technology will revolutionize how they find intelligence targets around the world, the newspaper said. The agency reportedly intercepts millions of images daily, including tens of thousands pristine enough to use for facial recognition.Federal privacy and surveillance laws have specific protections for facial images. The images were likely captured by the NSA from digital communications involving people overseas. The NSA would be required to get court approval for imagery of Americans collected through its surveillance programmes, as it does when reviewing their emails and phone calls, an NSA spokeswoman said. However, communications in which an American might be emailing or texting an image to someone outside the United States and targeted by the NSA could be an exception, The Times reports.