faceblur is a great application that will help you cover your friends faces in order to protect their privacy.
faceblur allows you to choose which faces you want protected and you have the possibility to leave some un-blurred.
NOTE: To buy faceblur via the AppStore an Apple account is required.
Here are some key features of "faceblur":
· accept all commonly-used image formats
· one click blur and one click un-blur
· does not change photo's resolution or quality
· select between high tone blur (white blur mask) and low tone blur (black blur mask)
· blur depth (transparency) can be easily set
· 64-bit processor