In your account settings you can change your profile picture. Click on the arrow top right next to your name, and choose “Account Settings.”
You will see on the left side “Profile Picture’. Click on it and you will be redirected to the page where you can change your profile and cover photo.
You can upload a photo from your computer by clicking on the ‘upload picture’ button.
Your can also adjust your cover photo. You can choose a predesigned cover photo, or add one yourself. Pay attention to the sizes of the cover photo, it has to be 1000×250.