The file earth.jpg is
http://apollo.spaceports.com/~jhasting/images/earthmaps/earthmap2k.jpg

This is a free earth map by James Hastings-Trew.  His other planetary
images are available at: 
http://apollo.spaceports.com/~jhasting

The file night.jpg is
http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/earth_lights_lrg.jpg

Details about this file can be found at
http://visibleearth.nasa.gov/cgi-bin/viewrecord?5826

This image is not copyrighted.  From
http://visibleearth.nasa.gov/help.html:

Unless otherwise noted, all images and animations made available
through Visible Earth are generally not copyrighted. You may use NASA
imagery, video and audio material for educational or informational
purposes, including photo collections, textbooks, public exhibits, and
Internet web pages.  This general permission does not include the NASA
insignia logo (the blue "meatball" insignia).

The file smile.png is converted from smile.gif, distributed with the
tik Instant Messenger application (http://tik.sourceforge.net).
