how to encode uiimageview in ios

i have a u开发者_运维知识库ser who has a avatar, i use uiimageview to save this avatar, so how can i encode avatar ? or you can give me a suggestion, how to encode user's avatar(image).

You can use UIImagePNGRepresentation() to convert a UIImage to a NSData which can be turned back to an UIImage again.