I don’t know how scientific it is to say that only introverts can see these images.
I can’t seem to find much research on the subject right away on the interwebs.
I did find other quizzes that state the same thing, but they didn’t have any links to evidence either.
I did find a lot of instances where designers or paint companies described colors as introverted and extroverted, and there is a decent amount of pop psychology, marketing, and human intuition that says bright colors are more extroverted and muted colors are the inverse.
However, I do believe this might be a good quiz to test your eyesight or focus or… something like that.
Or maybe you just have some fun.