A portrait of a nude woman has beaten more than 2,000 paintings to win a £25,000 art prize.
US artist Aleah Chapin's large-scale image, part of a series of naked women who she has known all her life, has scooped the BP Portrait Award.
The 26-year-old, whose oil painting, entitled Auntie, is of a family friend, wins £25,000 and a commission worth £4,000.
Aleah Chapin's winning portrait
"The fact that she has known me since birth is extremely important. Her body is a map of her journey through life," Chapin said.
"In her, I see the personification of strength through an unguarded and accepting presence."
National Portrait Gallery Director Sandy Nairne said the prize, which received entries from 74 countries, demonstrated "the vitality of contemporary portrait painting around the world".
He added: "Aleah Chapin's portrait is ambitious and beautifully painted, with superbly controlled colour and tone."
The £8,000 second prize went to Spanish artist Ignacio Estudillo for his black and white portrait of his grandfather.
Third prize was awarded to self-taught London-based artist Alan Coulson for his oil painting of his tattooed friend Richie Culver.
The BP Young Artist Award went to Welsh-born Jamie Routley, 29, for his triptych of newspaper seller Tony Lewis.
The BP Portrait Award exhibition, in its 23rd year, will open at the National Portrait Gallery in London on Thursday before moving to the Scottish National Portrait Gallery in Edinburgh and the Royal Albert Memorial Museum in Exeter.
Some 2,187 people, including almost 1,500 from the UK, submitted paintings for the award.
The National Portrait Gallery is among four of the country's top arts institutions who announced last year that they were renewing their sponsorship deals with BP, despite protests over connections with the oil giant since the Deepwater Horizon oil spill.