ABC News' Huma Khan reports: Secretary of State Hillary Clinton says she has "no idea" what she was watching with President Obama and his national security staff when the photographer snapped a picture showing her with her hand on her mouth and a tense expression. As of Thursday morning, the photo had been viewed nearly 1.9 million times and is on its way to becoming the most popular on Flickr, according to Wired. "Those were 38 of the most intense minutes. I have no idea what any of us were looking at that particular millisecond when the picture was taken,” Clinton said of the raid that killed Osama bin Laden. "I am somewhat sheepishly concerned that it was my preventing one of my early spring allergic coughs. So, it may have no great meaning whatsoever." The photo, taken by White House photographer Pete Souza, shows an anxious president and staff receiving updates on the mission taking place in Pakistan. It has garnered much speculation but the White House has remained mum on the details of what exactly was taking place when it was taken. Vice President Joe Biden was also reportedly holding his rosary ring. The White House released eight behind-the-scenes photos on Monday, illustrating the intensity of the situation. The photos show Obama making phone calls throughout the day to keep up with the developments, and meeting with his staff in the Situation Room. This is an updated version of this post.