Free wallpapers are available online at many websites such as Wickimedia Commons, which has a large collection of images that are free to use. Larger images are best for wallpapers that fill your whole monitor. Smaller images can be used to create a tiled wallpaper appearance. Any photo that is not copyright protected can be used as wallpaper on most computers.
National Geographic has many free high-quality wallpaper images available. NASA is constantly taking pictures of space exploration so you can get some stunning free wallpaper images on their website.
Any picture that is not copyright protected can sometimes be turned into a wallpaper image using a simple imaging program. Bing and Microsoft are great sources for a variety of images. Large companies and emerging artists sometimes offer images for wallpaper use. Flickr users share a lot of photos and many do not mind if they are used by others. Deviantart.com has a large selection of digital art images for download if you want a more futuristic look for your computer. Wallpaperstock.net is an easy to use site with a wide variety of images and resolutions sizes, so it is easy to find a wallpaper that suits your mood and personal style.