Step 1:
• Open PhotoBooth (Applications or Spotlight)
• Take a professional photo
Step 2:
• Click on your name (upper right corner)
• Click on "Settings"
Step 3:
• Click "Browse"
Step 4:
• Click your photo
• Click open
• Click "Photos" under MEDIA
• Click "Submit"
(If PhotoBooth has filled the screen, click the ESC key to exit after you have taken your photo).
• Click "Profile Photo"(under Personal Settings, upper left corner of screen)
• Click Photo Booth
• Click "Save"