GIMP - GIMP is a multiplatform photo manipulation tool.
Flickr - image and video hosting website
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
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.
Google Photos - All your photos are backed up safely, organized and labeled automatically, so you can find them fast, and share them how you like.