Accepting that big "useless" images are indeed ignored (as per the Yale School of Management example), how does adding them or removing them affect the conversi

Accepting that big "useless" images are indeed ignored (as per the Yale School of Management example), how does adding them or removing them affect the conversion rates? To rephrase: what if they are completely ignored by the eyes but they add to the website in a way that increases the conversion rate? What if having these images made the websites be perceived as more "professional" and thus increases sales? In short: what if eye-tracking is not the correct and only way to measure the effectiveness of these images?