A Polish collector has unveiled a photograph of composer Frederic Chopin, taken after his death in 1849.

Polish gallery owner Wladyslaw Zuchowsk claims to have acquired the daguerreotype, an early form of photograph, in Scotland and had it restored in London.

The sombre eight by seven cm portrait is said to show Chopin in the moments following his death. It is signed by Louis-Auguste Bisson, a well-known 19th-century French photographer, who also captured the composer earlier that year.

"Everything suggests that this is an authentic picture," Zuchowsk told AFP.

"It is the only known daguerreotype of Chopin. Every other known picture of the composer is a copy."

Some experts and investors are yet to be convinced of its authenticity. Chopin expert Steven Lagerberg believes the photo "is a fake, and a rather poor one at that".

Lagerberg explained that the image does not resemble the composer and that the people who sat with Chopin during his last days never mentioned a photograph being taken, despite the fact that the procedure would have taken hours.

"The absence of good photographs of Chopin allows this sort of fakery to be taken seriously," added Lagerberg.

One of only two authenticated photos of Chopin. Taken in the year of his death by Bisson.

If authentic, it would be only the third original photograph of Chopin in existence, and could achieve a considerable price at auction.

In 2008 the autographed manuscript of Chopin's The Tarantella Op.43 achieved £409,250 at a Sotheby's auction.