I use Snapseed on Android. It's a practical app with many photo editing tools
I like how I can edit my photos here,
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 .
Ralpha Image Resizer - High-speed image batch conversion tool
PicsArt - Explore 100,000,000+ awesome images and photos on the web
ImBatch - ImBatch is a batch image processor with a nice graphical user interface.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Caesium Image Compressor - Compress your pictures up to 90% without visible quality loss.