Gagosian GalleryBob Dylan in the late 1980s. He has proved elusive when questioned on his sources.

Marcus Yam for The New York Times“Trade” by Bob Dylan.

Henri Cartier-Bresson/Magnum PhotosA Henri Cartier-Bresson photograph from 1948.

The freewheeling artistic style of Bob Dylan, who has drawn on a variety of sources in creating his music and has previously raised questions of attribution in his work, is once again stirring debate — this time over an exhibition of his paintings at the Gagosian Gallery on the Upper East Side.

When the gallery announced the exhibition, called “The Asia Series,” this month, it said the collection of paintings and other artwork would provide “a visual journal” of Mr. Dylan’s travels “in Japan, China, Vietnam and Korea,” with “firsthand depictions of people, street scenes, architecture and landscape.”

But since the exhibition opened on Sept. 20, some fans and Dylanologists have raised questions about whether some of these paintings are based on Mr. Dylan’s own experiences and observations, or on photographs that are widely available and that he did not take.

A wide-ranging discussion at the Bob Dylan fan Web site Expecting Rain has pointed out similarities between several works in “The Asia Series” and existing or even well-known photographs — for example, between a painting by Mr. Dylan depicting two men and a Henri Cartier-Bresson photograph of two men, one a eunuch who served in the court of the Dowager Empress Tzu Hsi.

Marcus Yam for The New York TimesBob Dylan’s painting “Opium,” on view at the Gagosian Gallery in Manhattan.

Musee d’Albert KahnLéon Busy’s photo “Woman Smoking Opium,” similar to the painting, is part of a debate about Mr. Dylan’s work.

Observers have pointed out that a painting by Mr. Dylan called “Opium,” which is used to illustrate a Web page for the “Asia Series” exhibition on the Gagosian site, appears to be closely modeled on a picture by Léon Busy, an early-20th-century photographer.

Separately, Michael Gray, in a post on his blog, Bob Dylan Encyclopedia, points out that a painting by Mr. Dylan depicting three young men playing a sidewalk board game is nearly identical to a photograph taken by Dmitri Kessel.

Mr. Gray, an author who has written extensively about Mr. Dylan’s work and its artistic influences, writes on his blog:

“The most striking thing is that Dylan has not merely used a photograph to inspire a painting: he has taken the photographer’s shot composition and copied it exactly. He hasn’t painted the group from any kind of different angle, or changed what he puts along the top edge, or either side edge, or the bottom edge of the picture. He’s replicated everything as closely as possible. That may be a (very self-enriching) game he’s playing with his followers, but it’s not a very imaginative approach to painting. It may not be plagiarism but it’s surely copying rather a lot.”

Others commenting at Expecting Rain were less concerned, like one using the screen name restless, who wrote: “ ‘quotation’ and ‘borrowing’ are as old as the hills in poetry, traditional songs, and visual art.”

“There’s no need to be an apologist for that,” the post continued. “It’s often a part of making art, that’s all. Good grief, y’all.”

On Monday a press representative for the Gagosian Gallery said in a statement: “While the composition of some of Bob Dylan’s paintings is based on a variety of sources, including archival, historic images, the paintings’ vibrancy and freshness come from the colors and textures found in everyday scenes he observed during his travels.”

The gallery also pointed to an interview with Mr. Dylan in its exhibition catalog, in which he is asked whether he paints from sketches or photographs. He responds:

“I paint mostly from real life. It has to start with that. Real people, real street scenes, behind the curtain scenes, live models, paintings, photographs, staged setups, architecture, grids, graphic design. Whatever it takes to make it work. What I’m trying to bring out in complex scenes, landscapes, or personality clashes, I do it in a lot of different ways. I have the cause and effect in mind from the beginning to the end. But it has to start with something tangible.”

Mr. Dylan has previously proved elusive to critics and observers who have tried to pin him down on source material. In 2006 it was shown that lyrics on Mr. Dylan’s No. 1 album “Modern Times” bore a strong resemblance to the poems of Henry Timrod, who composed verses about the Civil War and died in 1867. Lyrics from a previous album, “Love and Theft,” were similar to passages from the gangster novel “Confessions of a Yakuza,” by the Japanese writer Junichi Saga.

In a 2008 essay for The New Haven Review, Scott Warmuth, a radio disc jockey and music director who has closely studied Mr. Dylan’s work, said that Mr. Dylan’s 2004 memoir, “Chronicles: Volume One,” had adapted many phrases and sentences from works by other writers, including the novelist Jack London, the poet Archibald MacLeish and the author Robert Greene.

Mr. Dylan did not comment on those similarities then, and a representative for him declined to comment on the Gagosian exhibition.