Adding a profile picture
Step 1
In the bottom left-hand corner, click view profile.

Step 2
On the left. click Change.

Step 3
Select the photo you'd like to upload from your computer
Step 4
Click Submit

Editing your profile picture
This process is actually identical to adding a profile picture, outlined above :)
Removing your profile picture
Step 1
In the bottom left-hand corner, click view profile.

Step 2
A preview of your profile picture will appear on the left. Click remove beneath it.
Step 3
Click Submit

Note
You are the only person that can edit your user account. This includes editing your profile picture.