From the My Profile page, hover your mouse above the hexagonal picture or blank avatar and a camera icon and “Update Profile Picture” message will appear. Click on this and select your new picture.
From the My Profile page, there will be a wheel icon and Edit button you can click on. Then you can click on the circular icon with your current picture or blank avatar. You will then have options to capture a new photo with your phone camera, upload an existing photo, or remove the current photo.