Unsplash - Unsplash is a website with high-quality free HD images. It has a catalog of more than three hundred thousand striking images that are neatly organized with tags. Read more about Unsplash.
Flickr - image and video hosting website
Pixabay - Over 270,000 free photos, vectors and art illustrations
Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
Openverse - Openverse is an Openly Licensed Images and Audio database and a growing community of photographers, illustrators, and musicians who share their work under a Creative Commons license.
Google Photos - All your photos are backed up safely, organized and labeled automatically, so you can find them fast, and share them how you like.