LONDON (Reuters) - A set of 107 non-fungible tokens (NFTs) representing images of cartoon apes sold for $24.4 million in an online sale at Sotheby’s auction house on Thursday, as the market for the niche crypto asset continues to heat up. The images were part of the “Bored Ape Yacht Club” collection of NFTs - a set of 10,000 computer-generated cartoon apes, made by the U.S.-based company Yuga Labs. Owners of the ape NFTs become members of an online club. An NFT is a digital asset that uses blockchain technology to record who owns a digital object such as an image, video or in-game item. While anyone can view the asset in question, only the buyer can say they are the “official” owner. Unusually for NFTs, the buyers of Bored Apes also receive the intellectual property rights for the images. They are often used as profile pictures on social media. The lot contained 101 of these anthropomorphic apes, with different combinations of features such as clothing, accessories and facial expressions, plus the option to generate six new “mutant” ones. The sale also included a lot of 101 “Bored Ape Kennel Club” NFTs - a set of dogs, marketed as pets for the apes. This fetched $1,835,000 and the set of apes fetched $24,393,000, bringing the total for the sale to $26,228,000. Sotheby’s allowed payments in the cryptocurrencies bitcoin, ether and USDC, and fiat currency. RAPID GROWTH The frenzy for NFTs shows no signs of slowing. Sales volume on the largest NFT marketplace, OpenSea, hit $3.4 billion in August, up tenfold from July. Some speculators “flip” their NFTs for eye-watering profits within days or even hours. The average weekly secondary market price for a Bored Ape has surged from around $1,500 when they were launched in April to $71,942 last week, according to NonFungible.com, a website that tracks the NFT market. On Monday, a single Bored Ape sold for 740 ether (around $2.9 million).Michael Bouhanna, contemporary art specialist at Sotheby’s, said that although there is financial speculation on NFTs, he sees the Bored Apes as works of art. He said the NFT market is not a bubble. “People were talking about a bubble in March, in June, etc, and then we see that the market is even stronger today so I think they’ve been proven wrong ... I think it’s a very organic market with great collectors who have great appreciation of art,” he said. Graphic: Bored Ape Yacht Club NFTs price surge -