Seattle-based Getty, which produces editorial content and creative stock images and video, accused Stability AI of using its images to “train” its Stable Diffusion system, which can generate images from text inputs.

The company had sued Stability AI for breach of copyright on the grounds Stable Diffusion was trained using Getty’s images, and that images generated by Stable Diffusion reproduced its copyrighted images.

But Getty dropped that part of its case mid-trial, partly due to a lack of evidence about where Stable Diffusion was “trained”, which intellectual property lawyers said could limit the wider significance of Tuesday’s ruling for the law on AI.

Getty’s claims of trademark infringement and for secondary copyright infringement, alleging that Stability AI imported into the United Kingdom an AI model which breached its copyright remained live ahead of the court’s decision.

Judge Joanna Smith said in a written ruling that Getty had succeeded “in part” on trademark infringement, but that her findings were “both historic and extremely limited in scope”.

She also dismissed Getty’s secondary copyright infringement claim.

The company’s shares were seen down 6.6% in premarket trading following the ruling.