Here is a list of some really excellent Internet sources for public domain/open access/copyleft images for art, architecture, and landscape. Remember that these images need to be referenced just the same as any copyrighted imagery. Many of these sites require registration or log in, and some mix open access images with images for which a fee must be paid for permission.
Art and Architecture books for free (legally):
Internet Archive: https://archive.org/search?query=architecture%20AND%20mediatype%3Atexts
Project Gutenberg: https://www.gutenberg.org/ebooks/search/?query=Architecture
Loyal Books: https://www.loyalbooks.com/book/on-architecture-by-vitruvius
E-Books Directory: https://www.e-booksdirectory.com/listing.php?category=108
ManyBooks: https://manybooks.net
Metropolitan Museum of Art: https://www.openculture.com/2018/11/download-569-free-art-books-metropolitan-museum-art.html
Image sites:
Arquigrafia (in Brazilian Portuguese) https://www.arquigrafia.org.br/home

Leo Belgicus, Anonymous, 1610. Bibliothèque Nationale de France.
Banque d’Images, Bibliothèque Nationale de France.https://www.bnf.fr/en/banque-dimages-picture-collection
Conway Library at the Courtauld https://photocollections.courtauld.ac.uk/sec-menu/search/?fq%5B%5D=search_s_collection:%22The%20Conway%20Library%22&mode=gallery&view=horizontal&sort=random%7B1753281946562%7D%20asc&filterAction

George Steuart Mackenzie. Travels in the island of Iceland. Edinburgh: Printed by T. Allan for A. Constanable, 1811. Aquatints with hand coloring. Cornell University Library Rare and Manuscript Collections.
Cornell University Library Rare and Manuscript Collections https://rare.library.cornell.edu . 60 collections to browse.
Cornell University Library PJ Mode Collection of Persuasive Cartography: https://persuasivemaps.library.cornell.edu
Duke University Libraries Ad*Access. 7,000 US and Canadian advertisements. https://repository.duke.edu/dc/adaccess. Just one of 1,491 collections at Duke. https://repository.duke.edu/dc
https://www.flickr.com/ – British Library Flickr account, for example, is full of open access images: https://www.flickr.com/photos/britishlibrary/
Getty Image Archive. Tick the box to show only open content. https://www.getty.edu/art/collection/search?open_content=true

Stereoscopic image showing a small boy climbing a ladder beside a chimney breast, a young girl standing in the doorway of the property as a woman crouches on the ground holding a bucket, outside their home in the Turpentine region of North Carolina, circa 1903. (Photo by Underwood & Underwood/Graphic House/Archive Photos/Getty Images)
Getty Black History and Culture Collection provides use for educational purposes. https://dam.gettyimages.com/black-history-culture-collection/getty-images-black-history-culture-collection-view/
Library of Congress, USA. www.loc.gov/pictures/

General Plan of the Château and Petit Parc at Versailles, Israël Silvestre, 1679. Collection of the Louvre.
The Louvre, France. https://www.openculture.com/2021/03/the-louvres-entire-collection-goes-online.html https://collections.louvre.fr/en/
Maptiler https://cloud.maptiler.com/
Metropolitan Museum of Art. https://www.metmuseum.org/art/collection 492,000 public domain images. If you see an “OA” icon and the words “public domain” (as shown in the example below), you’re free to use the image, provided that you abide by the Met’s terms.

Double-Decker Bridge Over the Susquehanna River between Perryville and Havre de Grace on US 40, Records of the Bureau of Public Roads, 1939. National Archives.
National Archives (US) https://www.archives.gov/research/still-pictures
Newberry Library Digital Collections https://collections.newberry.org
New York Public Library. Over a million images. https://digitalcollections.nypl.org
Old Maps Online https://www.oldmapsonline.org/en
Open Culture: this is the opening to a portal of amazing amounts of free stuff from language lessons to films. https://www.openculture.com/
Openverse. Stock photos, images, and audio. 800 million creative works. https://openverse.org/

Anthropomorphic Landscape, Wenceslaus Hollar, 1620. Public Domain Image Archive
Public Domain Image Archive https://pdimagearchive.org/
Public Domain Review https://publicdomainreview.org/
Public Domain Review Sources. A treasure trove! https://publicdomainreview.org/sources/

Architectural Project for the house of P.J. Hetzel, Eugène Emmanuel Viollet-le-Duc, 1874. Smithsonian Open Access.
Smithsonian Open Access https://www.si.edu/openaccess
Undraw. Open source illustrations. https://undraw.co/
Unsplash. Open source photography. https://unsplash.com/
Wellcome Images https://wellcomecollection.org/search/images

The Erechtheum at the Acropolis, Athens with evening moon. Image by Jebulon, 2015, Wikimedia Commons.
Wikimedia Commons https://commons.wikimedia.org/wiki/Main_Page
Wikidata https://www.wikidata.org/wiki/Wikidata:Main_Page
And here is how to contribute to the effectiveness of open source imagery: https://diff.wikimedia.org/2025/07/27/tidbits-for-commons-contributions-you-dont-have-to-be-a-photographer/
Thank you for all the suggestions to compile these resources: Amrita Kaur Slatch (LinkedIn), Ben Berry @bengerman@hachyderm.io, Benjamin Flowers @benjy-flowers.bsky.social, Cécile Archives @cecilearchives.bsky.social, Dr Susi Arnott @SusiArnott@mastodon.green, Gabriel @arrobagaf.bsky.social, Geeks anciens @GeeksAnciens@sciences.re, Jenni @jenni@appdot.net, Joey Donovan (LinkedIn), Jorge Bejarano @guayabito@mastodon.cr, Kerstin Sailer (LinkedIn), Korawich Kavee @kkavee@urbanists.social, Mark Stoneman @markstoneman@zirk.us https://markstoneman.com/lists/images/ Modernism in Metroland @modinmetro.bsky.social, Pax Ahimsa Gethen @funcrunch@me.dm, Pratik Chakrabarti @pratik-hstm.bsky.social, Sebastian Lasse @sl007@digitalcourage.social, Sewicked @sewicked.bksy.social, Your pal Al @al@social.coop