Your profile picture and an avatar are two different things. Although you may use the same picture for both (or different), they must be sized appropriate and uploaded as two different things.
Your choice of picture for your profile, only shows up in your profile.
Your choice of picture for an avatar, is what shows up in your posts under your username.
I checked your account and you don't seem to have an avatar set, and only a profile pic.
If you are wanting to use the pic that dea49 sized appropriate for an avatar, you can download it and then upload it as an avatar to your account using these instructions;
...... or I can do that for you.
When you go to your user CP, you will see the options like I have a screenshot snippet below. You want to edit your avatar (in red) and not your profile pic (in blue)