Same strategy as Adobe's Firefly, which was trained on their catalog of stock images.

Not so long ago many predicted that stock image sites will eventually become obsolete or at least much less important due to AI image generators. But it might turn out that stock image sites are uniquely positioned to dominate commercial AI image generation because of the "ethically sourced" high quality training data they posses.

They might still have minor legal fights whether this is a legal way to use the data licenses to them, but the list of people who could possibly sue is much shorter, known to the stock image site, and consists of people who have already signed some form of contract about the use of these images. The legal risks are well scoped and predictable, unlike "we scraped the internet" models.