A round-up of the latest news from the art world, including a photograph of Barack Obama and the Tiger of Mysore.

A tiger's head from the golden throne of Tipu Sultan (1750-99)

A gem-encrusted finial in the shape of a tiger's head from the golden throne of Tipu Sultan (1750-99), the "Tiger of Mysore", who was the East India Company's most ferocious opponent in the pre-colonial India, sold last week for £389,600 at Bonhams. The finial had been removed from Tipu's throne following the capture of his capital city, Seringapatam, by the British army in 1799, and had lain in Featherstone Castle, Northumberland for 100 years, and then in a bank vault unknown to Tipu scholars, before it was discovered by Bonhams on a routine valuation. Another golden tiger's head from the throne is at Powis Castle while other examples of the Tipu treasures are to be found at the Victoria and Albert Museum and in the Royal Collection. Bonhams had not placed an estimate on the tiger's head, saying it would allow the market to take its course. Bidding started at £200,000 before ending with a telephone bidder whom Bonhams describes as being neither Indian nor British.

The original photograph of Barack Obama on which artist Shepard Fairey based his famous campaign image of the future President is being sold by a gallery in New York. The photograph, which was taken for the Associated Press in 2006 by freelance photographer Mannie Garcia, while on a consignment to photograph George Clooney when Obama was the junior senator from Illinois, was found by Fairey on the internet. Subsequently Fairey was accused of copyright infringement by the Associated Press who demanded payment for its use. Fairey has acknowledged using an AP photograph but has claimed that he is protected under fair-use exceptions to copyright law. "It's going to be a landmark copyright case," says dealer James Danziger of Danziger Projects, a former Sunday Times picture editor, who is selling Garcia's photograph in an edition of 200 for $1,200 each.

Sotheby's auctions in Hong Kong have got off to a good start. Half-way through the four-day series, they have realised $50 million, nearly double their pre-sale estimate. A collection of 9,000 bottles of classic wines sold out for $6.4 million, six times the estimate, and sales for traditional Chinese and modern 20th-century paintings have also exceeded estimates. Contemporary Asian art has been slightly more subdued, though most of the more valuable works have sold, some for record prices.

The first sale devoted to African contemporary art is to be held by Bonhams in London on Wednesday. The exotic assortment includes works, many made only last year, by artists from six different countries, though it was the booming market for artists from Nigeria that triggered the sale. Last December, Bonhams sold a painting by the late Benedict Enwonwu for £19,200, 20 times its estimate, and prices for the Nigerian-based artist El Anatsui have fetched as much as £350,000 in other contemporary art auctions. Both artists are included in the sale together with a strong contingent of South African artists. Among the lots are two prints by Nelson Mandela seeking to become the first works by the former President of South Africa to sell at auction.