Flickr - image and video hosting website
Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
Piwigo.org - Manage your photo collection with Piwigo. Piwigo is open source photo gallery software for the web. Designed for organisations, teams and individuals.
ImageShack - Unlimited space to host images, easy to use image uploader, albums, photo hosting, sharing, dynamic image resizing on web and mobile.
500px - Connect, get inspired, and grow your skills.
YouTube - Our mission is to give everyone a voice and show them the world.