I use Snapseed on Android. It's a practical app with many photo editing tools
I like how I can edit my photos here,
Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
VSCO - VSCO® is an art and technology company empowering people everywhere to create, discover, and connect. CompanyVSCO® is a trendsetting art and technology company that .
Flickr - image and video hosting website
PicsArt - Explore 100,000,000+ awesome images and photos on the web
Photobucket - Photobucket offers image hosting and free photo and video sharing.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.