You want to change your profile picture, let’s follow these below steps:
Step 1: Log in https://outlook.live.com, using your current username and password. You will be prompted to the Outlook homepage. There are your email options on the left and personal details on the right. Click on your username, you will see a number of preset setting options.
Step 2: Click “View account."
Step 3: Choose "Add a photo”.
Step 4: Click Add a picture and choose the picture from your computer to be added in your profile picture.
Step 5: Click Save.