To change your profile picture, first click on the settings icon from the main menu.
Next click on the globe icon.
The next screen has a list of the different social media options you can log in with. Your MSM2 profile picture is the same as your social media account profile picture. You can hit the arrows next to your current picture to change between your different social media accounts. The more accounts you connect with, the more options you will have. You cannot upload your own profile picture. Only your social media profile pictures can be used.