Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
Flickr - image and video hosting website
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Photobucket - Photobucket offers image hosting and free photo and video sharing.
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.