IN a closely watched copyright case with broad implications for the contemporary-art world, the United States Court of Appeals for the Second Circuit on Thursday decided largely in favor of the artist Richard Prince, who was found by a federal court in 2011 to have illegally used photographs from a book about Rastafarians to create a series of collages and paintings.

The original decision, by Judge Deborah A. Batts, sided with Patrick Cariou, whose 2000 book, “Yes Rasta,” featured portraits he took in Jamaica. Mr. Prince used dozens of the pictures as the basis for a series of dystopian works called “Canal Zone,” which were exhibited at the Gagosian Gallery in 2008 and generated more than $10 million in sales.