Denise Thwaites A Christie's auction. Source: Christies. Since May 2007, US-based digital artist Mike Winkelmann (who goes by the name Beeple) has posted a new artwork online every day. He posted the 5,000th one in January, and has now packaged them into an enormous digital collage titled Everydays: The First 5000 Days, which will be auctioned online by Christie’s on February 25. The work will be sold in purely digital form, as a 21,069 × 21,069-pixel JPEG file and a “non-fungible token” or NFT. NFTs use blockchain technology to give the successful bidder unquestioned ownership of the work. NFT artworks are becoming a serious business. Last year, Beeple made US$3.5 million on an NFT auction.