If you look in your User CP (button in the upper left portion of the page), you'll find that you've created a "Profile Picture" in the "Your Details" part of your User CP, but you haven't created an "Avatar". The Profile Picture can be viewed only on your Profile page. If you want an image to show up under your username in each of your posts, you'll need to click on "Edit Avatar" under "Settings and Options" and upload an image. The maximum size of your custom avatar image is 120 by 120 pixels or 97.7 KB (whichever is smaller). If you don't have image editing capability on your computer, you can Google
"online image editing" and find a number of free resources.