Digital pedals: also show the display and powered-on state

For multi-effects, pedalboards and digital units, add a powered-on image where useful.

Show:

• readable display;
• LEDs;
• any error messages;
• general condition of switches;
• main ports.

A powered-on photo does not prove every function, but it can document the display condition and basic startup.

Avoid exposure settings that make the screen completely white or unreadable.