Whosthat for iOS is a simple but powerful application that helps with the task of quickly tagging every person in ann image.
Whosthat uses face recognition to identify people in an image. Add a legend to the left, right or bottom of the image and label the people in the image. Often used people can be reused so you don't need to re-enter names all the time.
You can Add or Remove people to the image, reposition and change the sizeof the selected area. The size of the legend can be adjusted with the slider.
Use different colors to tag people, and use a number or short names to tag the people.
You can import an image from your Gallery, or get it from your iCloud Drive or Dropbox.
You can share the image to any available extension like Mail, Facebook or Google+ ...