To use the picture viewer on Windows 10 in the same way as on Windows 7, the following settings must be made.

1. call up regedit with the Window key + R by running as administrator
   
2. navigate to the following path in regedit: „HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Photo Viewer\Capabilities\FileAssociations“.
   
3. in this field, right-click on „New“ and select „String“
   
4. now enter the file format as the character string and confirm.
   
5. repeat this with these file formats, each with a new key:

.jpg
.jpeg
.bmp
.png
.gif

6. all new entries must then be edited again. The value PhotoViewer.FileAssoc.Tiff must now be entered entry by entry.
   
7. then select an image of the above-mentioned file format, right-click on Open with… and then select Other app.
   
8. now select the Windows photo viewer and tick the option Select as default app. Confirm with OK.

Photos will now be opened in the old Windows photo viewer again. This process may need to be repeated after each Creators Update.