WASHINGTON — The Inauguration Day photograph of a mitten-clad, glamour-defying Bernie Sanders perhaps was not the most flattering image of the US senator, but it has become a remarkably charitable one.

The 79-year-old lawmaker from the northeastern state of Vermont announced Wednesday he has raised US$1.8 million (S$2.4 million) for charity over the past five days through sales of merchandise featuring him wearing knit mittens and a parka at President Joe Biden's Jan 20 swearing-in.

The image launched a thousand memes and made the earnest and seemingly cantankerous two-time presidential candidate even more of an internet star than he already was.

"Jane and I were amazed by all the creativity shown by so many people over the last week, and we're glad we can use my internet fame to help Vermonters in need," Mr Sanders said in a statement. 

"But even this amount of money is no substitute for action by Congress," he said, referring to efforts to pass a massive coronavirus pandemic rescue package.

"I will be doing everything I can in Washington to make sure working people in Vermont and across the country get the relief they need in the middle of the worst crisis we've faced since the Great Depression."

Mr Sanders's office said the groups receiving charitable funds include the Vermont operations of Meals on Wheels and the Vermont Parent Child Network.

The initial run of the "Chairman Sanders" merchandise sold out 30 minutes after the items — including sweatshirts and T-shirts — were made available online Thursday. There is now a weeks-long backlog of orders.

The image of a cross-legged Mr Sanders wearing a light blue mask and seated alone at the inauguration was captured by AFP photographer Brendan Smialowski.

According to Mr Sanders' office, as part of the licensing agreement to put the image on apparel and stickers, Getty Images, the agency that distributes AFP images in the United States, will donate its proceeds from the license to Meals on Wheels America.

Mr Smialowski has been impressed by the various iterations of his frame online.

"The internet is like a wild animal, tough to predict and hard to tame," he said.

"While I never expect or strive for my work to go viral or get memed, it doesn't surprise me in the sense that the internet and social media are unpredictable. Anything is possible." AFP