To set and change default apps in Windows 11, follow these steps:

  1. Right-click on the Windows desktop and choose "Open Windows settings".
  2. In Windows settings, choose "Apps" from the left navigation pane.
  3. Scroll down to the "Default apps" section.
  4. Under "Defaults", Windows 11 users can click on the app they want to change and then choose another default app from the list of available apps.
  5. If the app you want to change isn't listed, you' introspect its settings wheel to change its default association.

For specific apps like the Windows 11 Photos app, follow these steps:

  1. Press the Windows button + S to open the search bar.
  2. Enter "default apps".
  3. Under the "Apps" section, select "Default apps".
  4. In the next menu, select "Photos app" for default settings.
  5. Choose the Photos app or any other image viewer that you'd like to use as the default.

By following these steps, you can easily set and change default apps in Windows 11.