How can I change my profile picture?

On mobile devices:

In the conversation list:

1. Tap  Profile.
2. Tap  Settings.
3. Tap Account.
4. Tap Picture.
5. Tap  (iOS) or tap the Shutter  (Android) to take a new picture.
6. Tap the camera roll preview (iOS) or  (Android) in the lower left corner to choose a picture from your device.
7. Tap OK to confirm your new profile picture.