"She looks like the head bouncer in a security firm," one commenter posted on The Daily Telegraph's Web site.

The painting, by Paul Emsley, was unveiled at the National Portrait Gallery on Friday, and if nothing else, it successfully brought out the inner art critic in even non-art critics.

"I hate to be negative," someone posted on The Guardian's Web site, "but it's really tragically awful."

Mr. Emsley, who was commissioned by the gallery to produce the work, won the BP Portrait Award in 2007 for a painting of Michael Simpson, a fellow artist. The duchess, the former Kate Middleton, sat for him twice, and he continued painting from photographs he took.

The biggest complaint about the work, a head-and-shoulders portrait, is that it puts about 20 years, and possibly 20 pounds, on the duchess, who is 31 and as slender as they come (despite being pregnant). It is somewhat hazy, as if it were a photograph that had been heavily airbrushed to disguise the subject's age wrinkles.

Alastair Adams, the president of the Royal Society of Portrait Painters, told the BBC that the painting was admirably "straightforward and very pure."

Unfortunately for Mr. Emsley, who is unlikely to produce work that generates this degree of interest anytime soon, most art critics begged to differ.

"It looks as if the painter asked the subject to 'say cheese!' and then told her to scram and buy some clothes while he painted the photograph," David Lee, former editor of Art Review magazine, said in The Daily Mail. "It is perfectly adequate for the boardroom of a supermarket but entirely inadequate for a national collection."

Waldemar Januszczak, the art critic for The Times of London, said it was the boring type of royal painting "we've been really churning out for the last few hundred years in Britain."

In The Guardian, Charlotte Higgins said the painting made the duchess look undead, like a character in one of the "Twilight" movies. And the Daily Telegraph critic Mark Hudson compared the work to a "mawkish book illustration" that could have happily been used on the cover of a romance novel.

"If Kim Jong-un, supreme leader of North Korea, had a portrait painted of himself in a similar idiom, we'd all be crowing from the rafters about the pitiful taste of foreign despots," he wrote.

The general feeling was that although the painting did not reach the same level of badness as the fresco of Jesus Christ that was disastrously restored by a churchgoer in Spain, it was no Mona Lisa. On the other hand, it provided a fine opportunity for the public to engage in one of its favorite activities: finding novel ways to ridicule things connected to the royal family.

"Sneering at royal portraits is part of British culture," Mr. Hudson said, "and it might almost be that Mr. Emsley has sacrificed himself to allow that tradition to continue."