website URL: https://www.metmuseum.org/about-the-met/policies-and-documents/open-access

rights statement: https://www.metmuseum.org/policies/frequently-asked-questions-image-and-data-resources

The Metropolitan Museum of Art’s Open Access Initiative makes all public domain artworks and artifacts held at The Met available to the public through Creative Commons Zero licensing. These works can be used for commercial and non-commercial purposes without explicit permission. Attribution is not required, but it is recommended. High resolution images can be requested for a fee.

available materials: Over 492,000 images from The Met’s collection of public domain artworks