Enlarge / An image from Stable Diffusion’s training set compared (left) to a similar Stable Diffusion generation (right) when prompted with “Ann Graham Lotz.” (credit: Carlini et al., 2023)

On Monday, a group of AI researchers from Google, DeepMind, UC Berkeley, Princeton, and ETH Zurich released a paper outlining an adversarial attack that can extract a small percentage of training images from latent diffusion AI image synthesis models like Stable Diffusion. It challenges views that image synthesis models do not memorize their training data and that training data might remain private if not disclosed.

Recently, AI image synthesis models have been the subject of intense ethical debate and even legal action. Proponents and opponents of generative AI tools regularly argue over the privacy and copyright implications of these new technologies. Adding fuel to either side of the argument could dramatically affect potential legal regulation of the technology, and as a result, this latest paper, authored by Nicholas Carlini et al., has perked up ears in AI circles.

However, Carlini’s results are not as clear-cut as they may first appear. Discovering instances of memorization in Stable Diffusion required 175 million image generations for testing and preexisting knowledge of trained images. Researchers only extracted 94 direct matches and 109 perceptual near-matches out of 350,000 high-probability-of-memorization images they tested (a set of known duplicates in the 160 million-image dataset used to train Stable Diffusion), resulting in a roughly 0.03 percent memorization rate in this particular scenario.