I tried taking their little quiz and couldn't get past the first page. It asks me to imagine somebody I know, then asks which details I can observe. But those details are unobserved until the quiz asks me about them. The color of their clothing? I wasn't thinking about any specific clothing at all, but when prompted to I'm able to imagine that person in many different outfits. Vivid details of those clothes? Sure, I can imagine details, but the details aren't necessarily there in the "image" until I'm prompted to invent them. The possible answers to the question just seem... invalid. The details are neither dim nor vivid; the details are undetermined and flexible.
Maybe the quiz should first ask me to imagine that person in a specific circumstance, where those details are predetermined by my memory of that circumstance? Even then I still don't understand what the quiz really means by half these answers. What does it mean for an image to be "lively"? That it's moving around? Am I meant to be imagining a still image or a moving image? Depending on how I interpret these questions and answers, I could get completely different outcomes from this quiz.