Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
Flickr - image and video hosting website
Adobe Photoshop Express - Easily edit and share your photos in no time!
Photobucket - Photobucket offers image hosting and free photo and video sharing.
PicsArt - Explore 100,000,000+ awesome images and photos on the web