Additional profile functions are now available with the recent upgrade to the Sprint community. You can now not only add / change your avatar, but also add up to 4 additonal photos to your profile. This makes it easy for users to identify your posts. Please make sure your photos adhere to the Community Guidelines.
On the community select the Your Stuff dropdown and click on Profile
Select Change photo & avatar
Choose an avatar or upload one of your own
Upload up to 4 photos on the Profile Photo and Avatar page and click Finished
You can view your changes on your profile page.
Here are the step-by-step screens of this activity.