Welcome to the community! First things first, upload profile pictures!
If you have noticed, there are two different areas for profile pictures on your profile page (kind of like Twitter and Facebook). When you are uploading photos in the Edit Profile page, upload 2 of them. The first one that says "primary photo" will appear in the smaller photo box on your profile and the second one will appear in the bigger photo box to the right of the small one. See the screenshot below!
Also, if you want to update your avatar (little photo that appears in the header and next to your posts) then go to Edit Profile and scroll down to the Avatar section.