1. Start the registry editor (regedit.exe) and select HKEY_CLASSES_ROOT.
2. Press Ctrl + F to open the Find dialog.
3. Type systemfileassociations, enable “Keys” and deselect “Values” and “Data” check boxes.
4. Press ENTER.
You’ll now be taken to the HKEY_CLASSES_ROOT\SystemFileAssociations branch.
Expand the “SystemFileAssociations” branch by double-clicking on it
Scroll down until you see a subkey named “image”
Double-click “image”
Double-click “shell”
Double-click “edit”
Double-click “command”
src: https://answers.microsoft.com/en-us/windows/forum/windows_10-files-winpc/change-default-image-editor/4b01b777-338f-49c1-8300-9bcd7f60c160