Here's the way to get an avatar to show up on your posts.
(a) Right click on the picture of Daniel J. Travante below and choose Save As. . . (just save it to your desktop a someplace you know you can get to easily)
(b) Go into "Settings" (link on the upper left of each page I think)
(c) inside your profile (settings) you'll see a button that looks like a camera. When you click on it - you can upload the photo you saved to this site as your avatar, just path the upload to the picture you put on your desktop.
Here's a picture of my profile with yellow arrows to show you what I looked at.