Occasionally, Windows updates can remove your default photo/image viewer. These steps will help you select your default app for viewing images. 

 - Open the Windows start menu and begin typing "default". You do not need to type in a particular area. This will open a search option showing the Default Apps setting. Select the Default Apps option.

 - From that menu, select Photo Viewer. This will open a screen with available apps to use for viewing photos and images.  

 - Select the Photos app as the default. 

 - You can now close the settings menu using the "X" in the upper-right corner.