A-Z Databases

Art images from museums in Paris, many of which have no restrictions on use. (Public domain.) Go to the Collections tab. Web site is in French. The ones that are free to use without restriction are under the section labeled "libre de droit," and when you search, you can click a checkbox for "libre de droit seulment" to get only unrestricted use images in your search results.

Highly reputable Open Access resource for science, including biology, medicine, engineering, and interdisciplinary studies that intersect with those areas.