Drupal: How to upload/ change admin/user gravatar icon

1. First you must prepare your new gravatar icon.
   (48x48 pixel and the maximum size is 30 kB)
   
   
2. Go to Home> Administer> User Management > Users
   
   
3. Find user that you want to edit. Click Edit.
   
   
4. Delete current picture & Upload new picture.
   
   
5. Save changes.
   
   
6. Refresh the page and see the changes.