Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
Box - Box offers secure content management and collaboration for individuals, teams and businesses, enabling secure file sharing and access to your files online.
Flickr - image and video hosting website
Nubo - A self-hosted file sharing application in Haskell.
Photobucket - Photobucket offers image hosting and free photo and video sharing.
4sync - A wonderful application that links all of your computers and mobile devices together. Easiest way to back up and sync your files online. Cross platform file management in the cloud