Windows Photo Viewer is the default program in Windows 7 to view Photos, whenever you double click on a photo in your hard drive it will be opened by Windows Photo Viewer. When you install Picasa in Windows, Picasa Photo Viewer will be installed and it will be set as default photo viewer for JPG, BMP, GIF, PNG, TIF, TIFF and RAW image formats.
If you want to use Picasa to only upload and share pictures and want to view photos as usual with in native Windows Photo Viewer here is how to make that change.
Making Windows Photo Viewer again as default Photo Viewer from Picasa
1. Open Picasa, click Tools and select ‘Configure Photo Viewer’
2. When you’re on ‘File Types’ tab, select ‘Don’t use Picasa Photo Viewer’ and click ‘Ok’ to apply the changes.
That’s it you can now see pictures will be opened and displayed in Windows Photo Viewer again.
Happy photo viewing in Windows Photo Viewer.