Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
picinfinity - Picinfinity is an image retaining/proxy site.
LightShot - The fastest way to take a customizable screenshot.
Libris - Libris is an asset management for photos and videos.
Screely - Screely instantly generates dribbble-ready images. Simply upload your screenshot and we'll do the rest.
Flickr - image and video hosting website