1. Right-click on the icon of your choice and pick 'Save Picture As...'
2. Open your Instant Messenger application.
3. Select the Buddy Icon chooser.
4. Choose "Browse PC" to go to the location of the image file you saved in Step 1, and select the image you want to use for your buddy icon.
5. Click OK.

All "Downloads" are from the offical POTCO site if you wish to see the offical page please click here.