Currently, it's not possible to remove a profile picture entirely. However, you can upload a blank image or a different picture as a workaround.
Here’s how you can do it:
Go to your 'Home/Today' page
Select the 'Profile icon' in the top right-hand corner.
Click on the profile image in the top left-hand corner or on your existing picture.
A menu will pop up at the bottom, giving you the option to take a profile picture with your device's camera or upload an existing picture from an album. Select one.
Once you've chosen your new profile picture, click 'Choose' on the bottom right.
Your profile photo will upload to the top left corner of the screen, and a green banner will appear, confirming that you've successfully uploaded your new photo!
By following these steps, you can effectively change your profile picture to a blank image or a different one.