Hello jmckeon -
The pic is called an avatar. Here's how to add one next to your screen name:
Click on User CP (located on the far left side of the brown menu bar above)
When your Control Panel opens (gray box on left) scroll down to "Settings & Options"
Click on Edit Avatar
After the new box opens, I usually choose to go with, "Option 2 - Upload Image From Your Computer"
Click on Browse to select an image from your hard drive to upload as your avatar.
Using your left mouse button, double click on the image you would like to upload as your avatar.
*Note: You may have to resized your photo. The maximum size of your custom image is 100 X 100 pixels and 7K in size max (whichever is smaller).
Click on Save Changes and the photo will be uploaded and displayed on all of your posts.