For Windows Internet Explorer: Right-click on the image you would like and select "Set as Wallpaper."
For Windows and other browsers: Right-click on the image you would like, then select "Save as" and save it into a windows folder. Change the saved image from JPEG format to BMP format using paint software, then right-click on the desktop image and select "Property." Choose the saved image file from the wallpaper lists and click "OK."
For Mac OS: Right-click for a while on the image you would like, then select "Save as"and save the image on your computer. Go to "Control Panel," then to "Appearance," next to "Desktop" (for OS-X, go to "System Environment"and select "Desktop") and choose the saved image file from the wallpaper lists.