This download is a Windows background depicting No. 2807 at Stratford-Upon-Avon on 26 June 1960.
Click on the file link, and if you get a dialog box then 'save this file to disk' or if you get an application start up then save the file from the application. Alternatively, right-click on the link and save the file to your computer ('Save Target As...').
The file is available in two formats. The .zip format is much smaller and will download much more quickly. But if you download the . zip file you'll need a program to unzip the file. If you have such a program (e.g. winzip) then there is an extra step involved at this point in the process which is to unzip the file to a location of your choice (if you haven't done this already).
Next, right-click on your desktop, select 'properties', select 'background', then 'browse'. Point to where you saved the file (or unzipped it), and windows will copy the file to the correct location and set it as the Windows background. Set 'display' to 'stretch' if you want the image to be stretched to fill the whole desktop.