To update your profile picture:
In the top left corner of the app, tap on the 3 lines icon(hamburger menu).
A window will pop-out from the left hand side, click on your profile name under Squad Details, in this example 'Your Name Here*'.
You will be brought to the 'Edit Profile' page, at the top, you will see the option 'Edit Avatar'. Click on that. Then choose a photo from your device's photo album or even take a photo. Additionally, you can leave the squad from here as well.
After selecting your photo, you will click 'Save' at the bottom right of the 'Edit Profile' page.