In the upper right corner you will see your name.
Click it, and click Edit My Profile.
Scroll down till you see
You can change your profile picture on Gravatar.
Click GRAVATAR under your blank photo (or the current one if you have one already and want to change it.
Go to Gravator and follow the instructions.
You’ll need to have a photo handy before you start this of course.
By the way, on the NMUG website, if you add your personal website address, it will appear on everything you do on the site so we do NOT RECOMMEND DOING THAT. (I learned the hard way!)
But you can post, again on the NMUG website, a short bio of your interests etc, if so inclined.