1. On the right side of every page you will see your name with your
controls underneath. Click on Settings.
2. Select Profile in the left column if it isn't already
3. Click on your current profile photo or the blue man silhouette,
or the Choose File button.
4. Find the photo you want to use on your computer.
5. Click Open.
6. Click Save at the bottom of the Update Profile page.
The change may not happen instantly, but will eventually.