An extensive library of public-domain (i.e., Creative Commons Zero, which means you can copy, use, modify, and distribute for free, without obtaining permission from the creator [though you always should provide attribution]) images available for download in a variety of sizes/resolutions.

Like Unsplash, Pexels maintains an extensive library of public-domain and Creative Commons images. Photographers upload their work to these sites for exposure, not economic compensation. Both Unsplash and Pexels are great for finding “stock-y” photos.

Not only an excellent source for images in the public domain, but also for illustrations, vectors, videos, music, sound effects, and GIFs.

Over 200,000 images in the public domain. Take care to filter search results by “public-domain materials.”

Collection of public-domain media: images, books, films, audio, etc.

Millions of 2D and 3D digital items available. All items in Open Access collection in public domain. Culturally significant images.

Over 492,000 images in the public domain. Artistic/cultural significance.

Community-driven free image site.