It's simple
Go into your profile
Then scroll down and you will see Settings & Options
Click into Edit Avatar
Read below - follow instructions
You may upload a new custom image using the controls below.
Option 1 - Enter the URL to the Image on Another Website Option 2 - Upload Image From Your Computer Note: The maximum size of your custom image is 100 by 100 pixels or 19.5 KB (whichever is smaller).