Windows 10 - Restore Windows Photo Viewer - UNDO.reg
Windows Registry Editor Version 5.00
; created by Walter Glenn
; for How-To Geek
; article: https://www.howtogeek.com/225844/how-to-make-windows-photo-viewer-your-default-image-viewer-on-windows-10/
[-HKEY_CLASSES_ROOT\Applications\photoviewer.dll]