To get a custom profile picture on the firestorm support :

• Create an account on https://fr.gravatar.com/ (this is in collaboration with wordpress)
• You will have to register with the same email address that you use for your Firestorm account.
• Click on "Sign in with Wordpress.com" and accept.
• Click on "add image" then "upload" and finally "crop image".
• Select "This gravatar is suitable for display on all websites with any audience type"

The synchronization will be done automatically within a few minutes.