Also you can watch the video.
https://www.youtube.com/watch?v=x8BsNz0715U
- Go to desktop and create a new
Text Documenthere then open it.
- Paste the code below there.
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Photo Viewer\Capabilities\FileAssociations]
".tif"="PhotoViewer.FileAssoc.Tiff"
".tiff"="PhotoViewer.FileAssoc.Tiff"
".png"="PhotoViewer.FileAssoc.Tiff"
".bmp"="PhotoViewer.FileAssoc.Tiff"
".jpeg"="PhotoViewer.FileAssoc.Tiff"
".jpg"="PhotoViewer.FileAssoc.Tiff"
".ico"="PhotoViewer.FileAssoc.Tiff"
- Click
File->Save asthe text document then type file name asviewer.regand choose save as type asAll files. Finally, click save.
- Open the text document.
You're all set.

I love it as well there are 2 major reasons I like it. It is the quickest way to view a .PSD (Adobe Photoshop Document) file.
Second reason is also related to that and it is setting that PSD Preview as a Desktop Wallpaper otherwise without this viewer (Windows Photo Viewer) we have to first open Photoshop (takes a lot of time in opening), open that psd file, save as an image, jpg or png open it in Photos App and than set as a wallpaper from there or in settings > personalization > background.