Facebook CEO, Mark Zuckerberg was photographed in his office earlier this week, celebrating Instagram's 500 million monthly users. While a happy Zuckerberg posed for the image, one eagle-eyed Twitter user named Chris Olson pointed out a tiny detail, which could be a scary warning. 

Zuckerberg's laptop is visible in the image. A small piece of tape is visible on both the webcam and the mic port on his device. 

Mark Zuckerberg is one of the highest-profile businessmen in the world and would be an obvious security target. These small steps prevent anyone from listening into conversations held in Zuck's office or watching any activity that may go on. 

Many business and tech people worry about unauthorised surveillance. Edward Snowden warned the world about the issue of webcam surveillance in recent years and even FBI director James Comey has said that he covers his camera too. 

"I saw something in the news, so I copied it,” Mr Comey explained at an event earlier this year. “I put a piece of tape — I have obviously a laptop, personal laptop — I put a piece of tape over the camera. Because I saw somebody smarter than I am had a piece of tape over their camera."

This may not be a hi-tech solution to the issue, but it certainly seems to work.