For advanced users: gives you full control.
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts.jpe\UserChoice] "Progid"="Applications\photoviewer.dll" windows photo viewer download for windows 10
If you just want a reliable classic image viewer without any registry tweaks: from irfanview.com — it's faster than Windows Photo Viewer and supports more formats. For advanced users: gives you full control
Microsoft replaced it with the (a UWP app) starting with Windows 8 and 10. However, the old Windows Photo Viewer (from Windows 7 and 8) still exists in the system files of Windows 10 — it's just not set as the default image viewer. windows photo viewer download for windows 10