More than 5,600 artists signed an open letter protesting the auction, saying that the works used AI models that are trained on copyrighted work.

A representative for Christie's shared a statement about the issue. "From the beginning, two things have been true about the art world: one, artists are inspired by what came before them, and two, art can spark debate, discussion, and controversy," the statement reads. "The discussions around digital art, including art created using AI technology, are not new and in many ways should be expected. Many artists -- Pop artists, for example -- have been the subject of similar discussions. Having said that, Christie's, a global company with world-class experts, is uniquely positioned to explore the relatively new and ever-changing space of digital art: the artists, collectors, market and challenges."