WASHINGTON — It was a picture-perfect moment. As the Senate convened for the start of the 116th Congress, Elizabeth Warren and Bernie Sanders, fellow progressives and potential rivals for the presidency, shared a brief hug on the Senate floor just minutes after they were both sworn in for their new terms.

Then there was Mitt Romney, the former Republican presidential nominee, striding across the floor as a proud new member from Utah. Smiling new and old senators lined up alphabetically to take the oath of office from Vice President Mike Pence as their colleagues applauded on the floor in the midst of a government shutdown. It was a lot to take in.

But this being the stodgy Senate, there were no photographers on hand to capture the scene, since they are banned from the chamber. While accredited photographers were granted special access to the House gallery to take colorful shots of Nancy Pelosi returning as speaker, youngsters roaming the floor and the diverse freshman class settling in, the Senate remained a shutter-free zone, as it has been for virtually its entire history.

What a loss, thought Senator Roy Blunt, Republican of Missouri, as he surveyed the festivities.

“I was thinking none of this becomes part of the pictorial history of the country,” Mr. Blunt said.