In WordPress uploading a user avatar is not directly provided. It has the default way of extracting gravatar images which is set as user avatar. This is okay if the user has a gravatar account and has uploaded his avatar there but issue occurs when the user does not have a gravatar account. I.e., his avatar is not set. To overcome this issue and make users able to upload an avatar or profile picture directly from their computer, the Avatar Uploader plugin has been created.
This plugin allows users to upload custom profile pictures or avatars and customize their size and style. Learn More