If you mean your avatar picture, you have to go back to your profile and select "Customize Profile" and on the left side you should see "settings and options", and select "avatar". There's a profile picture (which it looks like you have) and an avatar. Hope that helps.
The avatar and the profile picture are separate, so you have to make sure there's a picture on each one if that's what you want. Profile pictures show on your profile, avatars show next to your posts, <------- Like this. You have to set them both individually. Hope this helps xx
