In Windows 7 when we double click on any picture it will be opened and shown in Windows Photo Viewer, default photo viewing program, things changed in Windows 8 -Photos app made as default program which shows photos by default in full screen. This app contains photos from library, Facebook, SkyDrive, Flickr (you need to add Microsoft Account) and from devices like Digital camera you connected to your Computer. If you want to always view photos on desktop with Windows Photo Viewer instead of Photos app, its just simple as setting the program you want as default one to view pictures.
Reasons to prefer Windows Photo Viewer over Photos app (Photos vs. Windows Photo Viewer)
Photos app shows single photo in full screen and doesn’t allows to view next and previous photos in a folder, lacks slideshow option. Where Windows Photo Viewer offers these and allows to rotate picture in clock or counter clock wise direction, you can also zoom into image contents something Photos app doesn’t offers.
To set Windows Photo Viewer on Windows 8 as default program to open photos
1. Click on Windows key, start typing default, double click on ‘default programs‘
2. In Set Default programs window select Windows Photo Viewer on left-side and click set this program as default, click Ok button.
If you want to open PDF files on desktop instead of Windows Reader set PDF Reader on desktop as default program.
We need to make few changes like these to Windows 8 to make it work like in Windows 7. Make a list of these changes on notepad and save it for future reference, you need to apply them whenever you reinstall or freshly install Windows 8.