Changing a profile or cover photo
If you want to chage a cover photo, simply click on the "photo icon" in the upper left corner and select an existing one from your profile photos or select from your computer, tablet or smartphone (upload).
If you want to change a profile photo, simply moving your cursor to your profile photo where the "photo icon" shall appear and click on it. Then select an existing one from your profile photos or select from your computer, tablet or smartphone (upload). If you are using your mobile device, just tap on the top of your profile photo, the same popup shall appear.
Removing a profile or cover photo
To remove a profile or cover photo you need to click on a "photo icon" in the upper left corner if you want to remove a cover photo or click on a "photo icon" on the top of your profile photo when the popup shall appear. At the bottom of the popup there is a option "Remove current photo", you can click on it.