Once the user uploads the profile or cover picture, from the upload form, they are asked to crop it. That's all fine, but it seems a lot of people get lost at the next step. So many users don't realize they then have to submit the picture by scrolling to the bottom of their profile page. This seems like an unnecessary extra step.
On major sites, there is no such extra step. And I think a lot of users aren't accustomed to having to confirm the upload again. This is resulting in quite a few profiles that aren't completed with a cover and profile picture. If you can suggest a fix, it would be appreciated.