Images definitely have their place. The desktop app this grew out of lets me attach photos to elements. But even simple structured positions and routes cover a lot of day-to-day cases: "switch at 110 cm, 15 cm from the left edge", cable runs section by section, etc.

For true old-house spaghetti behind walls, photos or sketches probably matter more. But for handoff and routine lookups, being able to ask for all switches in an area and their positions beats digging through scattered notes.