A new official portrait of President Trump has been unveiled by the White House, replacing an earlier photograph that was released for Mr. Trump’s inauguration this year.

The portrait, revealed by the White House in a short video on Monday, shows Mr. Trump wearing a red tie in a close-up against a dark backdrop. His face, bearing a stern expression, is accentuated by high contrast and dark shadows.

The lighting and background differ from the portrait released for Mr. Trump’s inauguration, which was more evenly lit but still subdued, and showed the president in a blue tie in front of an American flag.

It’s not clear how often presidents have updated their official portraits in past administrations. Some, like Barack Obama, have had new ones made between their first and second terms.

Unlike the traditional, painted portrait that is done during a president’s term, the official photograph is far easier to compose and is used for day-to-day functions. It hangs in American government facilities around the world, and at entry points to the country.

Mr. Trump’s portrait from his first term showed him standing in front of an American flag with a blue tie, brightly lit and smiling.

The absence of an American flag in the background of the most recent portrait is a departure from contemporary tradition. A gallery of past portraits on the website of the Library of Congress shows that a flag has appeared in every official presidential photograph since Gerald Ford’s, which was released by the White House in 1974. Mr. Trump wore a flag pin in all three portraits.

“What’s interesting is they’ve removed all references to the White House setting,” said Paul Staiti, a professor of fine art at Mount Holyoke College who has studied presidential imagery. “It’s not unprecedented. And to be sure, this makes it more personal. But I do wonder whether this is suggesting that Trump is not exactly an office holder, or not to be seen solely as the current representative of the United States.”

Before Mr. Ford, most presidents were shown against a plain backdrop, as Mr. Trump is in his latest portrait.

The new photograph has already been added to the White House’s website.