said 9 months, 3 weeks ago:
“If you have an avatar located on another website, you can fill in the following field so everyone can see your avatar! (Note this will take precedence over Gravatars.)”
Just copy the URL of the image you want to use and it should populate.
From what I saw, you have not linked your LinkedIn Profile to the forums, so it could be hard for SME to make the connection.