When I bought my first PC World magazine many many years ago, it came with a DVD and it contained many of the Windows themes available in the form of “.themepack” files. Back then I did not know about themes and I was so much excited to see how by installing the themes the whole look of Windows desktop changes to quickly. Nothing much has changed since then, these themes are still available for Windows and are aplenty everywhere online. You can download official themes from the Microsoft website or you can download third party themes too. A typical Windows theme contains the desktop wallpapers, cursors, screensavers and the set of rules that define how a window looks like.
Now I do not really care too much about the various themes but some of them contain really good wallpapers. For example, some of the themes available from the Microsoft’s website contain desktop background for various occasions like holidays, Christmas, New year’s day, summer, nature, animals and more. Fortunately, you do not have to install the theme in order to use these desktop backgrounds. You can just extract the desktop background from the .themepack files.
In order to extract the desktop backgrounds, you must first install a third party ZIP extractor like WinRAR or 7-Zip. After this, you can rename the downloaded .themepack files to .zip files. And then just double-click to open them and find the backgrounds folder inside them which contains all the JPEG wallpaper images. You can also right-click on these files and choose to extract the whole theme file to a sub-folder from where you can find and use the desktop background JPEG images. There will also be files other than the JPEG images, but they do not concern your objective at the moment and you can safely delete or discard them as you seem fit.
Conclusion: You can easily extract the JPEG desktop background images from the .themepack theme packages. This way you do not have to install the theme to use the desktop background images.