I am having a similar issue, but some users pics are fine and some are not - I have found it depend on the account type.

With some testing, this is what I have found out .... it seems that the broken profile pics is only a problem for "super users". (at least this is what I can confirm at this time)

For a regular user, they work fine. They can upload/update their profile pics as per normal. They can hit the profile pic dropdown and their uploaded pics will show in the list.  

If I take that same user and change them to a super user, the pic that was previously working stops working and the profile pic dropdown no longer works. Now, I can upload a file and it will end up in the user dir, but it doesn't get processed at all (auto-create the different sizes), and the dropdown shows nothing, and no pics show in the profile.

If I take that same user and change them back to a "regular" user, everything is fine once again.

So, Im not sure if this was by design or if this is indeed a bug?

May be an old issue but still is (was) an issue.

I was struggling with this issue today. I knon 100% I have had it working before.
Tried all suggestions here.
Installed a 733 and saw it working there.
Upgraded my dev instance to 733 as well (was on 732). No change :-(

What is differing? The SKIN.

Changed to the "Host: Gravity - 2-Col" skin on the page/tab UserProfile. And also the container to "Host: Gravity - Title_h2" but not sure if that makes a difference.

What do you know. It actually started working.

Will now try to see if I can spot if there is something missing in my other skin that is affecting this issue.

Cheers
Mikael