How to Download Desktop Wallpaper
First Step for Both Mac and PC
Save the featured calendar photograph to your desktop. To save, click on the image link or thumbnail. This will enlarge the photograph in a new tab or window. From there, right-click the image with your mouse and save to your desktop or picture folder.
On a Windows PC:
Right click on your desktop, and click properties.
Select the desktop tab along the top.
Click browse to find the photograph on your desktop or where you saved the image.
Select the centered preference.
Click "Apply" at the bottom, and then click "OK"
On a Macintosh:
Click on the little Apple in the upper left of your screen.
Click System Preferences.
Click on desktop and screen saver
Press the little plus at the bottom of the list in order to select the image. From there, go to your desktop folder (or where you saved the original image) and select the calendar photograph.
That's it, you're all set! Enjoy!
Read more: How to Change Your Desktop Background (Mac + PC)