For me the hard question to answer is whether I have aphantasia because people describing “actually seeing” things like with their eyes is an absolutely wild concept.

To answer the question I imagine an apple with three dots in a triangle, closely together. There is no color because there is no real image, it’s just an idea. As other have said if prompted the idea gets more detailed.

That said, when I tried to learn building mind palaces it has worked. I can “walk through” places I know just fine, even recall visual details like holes in a letterbox. But again, there is no image.