This tutorial is quite simple, but probably the most common question I am asked.

"How do I get a picture to show up on my post?"

Go to settings in the upper right of the forum (must be on the full desktop version of the site, not the mobile version).

Then find the "Edit Avatar" link on your left.

Upload your favorite photo, save changes, and you are done!

Give it a try and come and reply to this thread to see if it's working