The linked pictures can be set as your background by right clicking, or you can download one of the free wallpaper programs such as "Wallpaper Changer" from Microsoft and use it with the images you download from this and other sites. I've tried to provide a screen sized image as well as the full resolution JPEGs.
This page should grow over time as archival images are added.
Alamo Hueco Mountains,
New Mexico Bootheel,
Glacier Bay National Park 2005 and 2006
Alamo Hueco Mountains Archival Images
Southern Utah, Mostly Canyonlands National Park
Otero Mesa Petroglyphs (likely to be destroyed if drilling is allowed)
Gila Wilderness and Black Range Fall Colors
Northern New Mexico, Bisti Badlands and Angel Peak