If you want to change the default program for pictures, movies, music or other files, here is 2 possibilities how to do it.
Select Default apps.
Select which default you want to set and then choose the app. You can also get new apps in the Store.
Open file explorer and find the file you want to change default program for.
Rigt click on the file, select Open with and Choose another app
Choose the program you want to have as default and mark the field “Always use thiss app to open .xyz files”
This method is working only for every single specific file extension. For example if you set your default program for .jpg files, you can have different program for .png files.
Complete tutorial here: