An image type that places the product next to a person or a familiar object (a coin, a phone, a hand) to convey true physical scale, rather than relying on shoppers reading and mentally converting listed dimensions.
Targeted specifically at the 'looks different / bigger / smaller in person than I expected' sticking point (see Product Photo Pain-Point/Solution Strategy) — dimensions in a bullet point don't reliably prevent that complaint, a visual reference does.
Apply: When size-related disappointment shows up as a review sticking point, add an image placing the product beside a recognizable reference object or a person.