Stability AI

Stability AI publishes open-weight image generation models, which can be downloaded and run on your own hardware rather than accessed only through an API.

That matters for three reasons: cost at volume, the ability to fine-tune on your own images, and working with material that cannot be sent to a third-party service.

Running locally requires a capable GPU and some setup, and licensing terms differ between model releases — worth reading before commercial use rather than assuming open weights mean unrestricted rights.