Yeah nice but no. The claim that people believe that claims that are associated with images are more "true" is not substantiated by the study, because the existence of the image causes people to reinterpret the question. "The liquid in that particular thermometer is magnesium." being "true" is not the same thing as "The liquid in all thermometers is magnesium." being "true".
The questions have been interpreted differently due to the existence of the image, and the so-called study (done by the University of Bunghole Sniffers) is comparing an apple to apples, and not apples to apples.
The macadamia question is also the same. The existence of the image in the claim may elevate a statement's "trueness" but it also diminishes the statement's scope, thereby decreasing the likelihood that the reader/viewer is going to connect themselves (and what they believe) to the claim.
They believe the claim, but they don't give a fuck.
This isn't an exercise in marketing; it's an exercise in how easily stupid people can manipulate other stupid people into believing in a claim, not because there is an image associated with it, but because stupid people lack the ability to think.