After a flurry of more than 180 bids in the final hour, a JPG file made by Mike Winkelmann, the digital artist known as Beeple, was sold on Thursday by Christie’s in an online auction for $69.3 million with fees. The price was a new high for an artwork that exists only digitally, beating auction records for physical paintings by museum-valorized greats like J.M.W. Turner, Georges Seurat and Francisco Goya. Bidding at the two-week Beeple sale, consisting of just one lot, began at $100.