https://lizkohlerbrown.com/free-image-resources-for-artists/
https://www.flickr.com/commonsThe Flickr Commons is an amazing resource for vintage and modern images of every category imaginable. Their goal is to share hidden treasures from the world’s public photography archives. So universities, libraries, and other institutions around the world contribute high quality (and unexpected) photos. It’s not the best resource when you’re looking for something very specific, but if you’re in the mood to browse and get inspired (and maybe discover some hidden gems), this is the perfect place to go. (note: make sure you use the search bar that says “Search the Commons”, not the one at the top of the page)
https://www.flickr.com/photos/britishlibrary/albumsThe British Library’s collections offers millions of public domain images, which the Library encourages you to explore and re-use. Like the Flickr Commons library, it’s not the best place to find specific images, but you can find tons of inspiring images that will probably send you down a rabbit-hole of a new drawing series (just warning you).