Your profile image, or "avatar" can come from a few sources.
If you've connected your Facebook or Twitter account, we will use the image that you set on these sites. To change this image, you will have to log in to that site and follow the instructions.
If you have not connected another site to your account, we use a web site called Gravatar to generate a default image. To change your image, simply create a profile on Gravatar, following these instructions: