You have to give it some time.
Not so long ago, people had to wait more than a week before they could see their new avatar.
Refresh the page, and then go to your profile.
Check the following steps:
1. create a jpeg picture file
2. Attach it to 360
3. set as Primary picture
4. Save it
5. Give some time to update
6. If did not see, click refresh
You should be o.K. Good Luck!