Good for animals, good for people, not so good for animals and people together. When possible, credit for photos is appreciated.
Search for images you can reuse from a variety of sources - museums, Flickr, etc. You can also search the individual collections, for example, Animal Diversity Web, and limit the search by image type and size, file size, etc. "You must attribute the creator when you provide material to the public by any means that is restricted by copyright or similar rights. If you are using the material personally but are not making it or any adaptations of it available to others, you do not have to attribute the licensor. Similarly, if you are only distributing the material or adaptations of it within your company or organization, you do not have to comply with the attribution requirement."
Type in keywords and then limit your search by image size, type, region, domain, and most importantly, usage rights, so you can find images that are free to use.
Copyright free images and videos. You can search by keyword or browse the category: Animals and Humans. Attribution is not required. Giving credit to the contributor or Pixabay is not necessary but is always appreciated.
Freely usable images. Creating an account lets you create collections that let you organize photos you love or want to save for later projects.Has a category for People and Animals. You do not need to ask permission from or provide credit to the photographer or Unsplash, although it is appreciated when possible.
The full contents of Vogue magazine (US edition) in full color page image, from the first issue in 1892 to the present, with monthly updates for new issues.
Wikimedia Commons is a media repository that is created and maintained... by volunteers....it provides a central repository for freely licensed photographs, diagrams, animations, music, spoken text, video clips, media of all sorts.