For Yahoo Messanger

1. Right click on one of the pictures and click 'Save Picture As'
2. Open Yahoo Messanger
3. Click on the Messanger tab on the menu bar.
4. Click on Preferences (or click Ctrl+Shift+P)
5. Choose Display Image in the category window.
6. Click on Change Default
7. Click on Select a picture.
8. Click on Browse
9. Select the picture
10. Click on Ok

For MSN Messanger

1. Right click on one of the pictures and click 'Save Picture As'
2. Open MSN and click on the arrow by your screen name.
3. Click on 'Change My Display Picture'
4. Click on Browse
5. Select the picture
6. Click on Ok