Klout displays a photo imported from either Facebook or Twitter. If you want to switch which network your photo is from, go to the upper right-hand corner of your screen to where your name is located and select "Settings" from the drop down menu.
This will bring you to the "Profile Settings" tab. Here you will see the option to select a picture from your network of choice, either Facebook or Twitter.
Click on which picture you would like displayed on your Klout profile, then hit the "Save Settings" button. Please note that if you just added your Facebook or Twitter, it may take up to 24-48 hours after receiving a retweet, mention, comment, like, or wall post from another user for your picture to import.