JPG and other image files cannot be linked with other applications, e.g. IrfanView.
For many years I have been using IrfanView as an image viewer in Windows. It is much faster than the integrated Windows solutions and much more practical.
However, I noticed that JPG files were opened in Windows with the Windows photo viewer. So change it? Think again, in the Open with dialogue, the option to always open the file type with the program was missing. Instead, “Only once” was available for selection.
After a bit of trial and error and searching on the Internet, I found the solution. In the settings for Microsoft Photos there is the option “Reset”.
As soon as this is activated, we can use the “Open with” dialogue again. The “Always” option now appears here.