Something to think about.

If you imagine an image in your mind, what are the spacial dimensions of the object you're imagining? If I imagine a planet, is it a miniature planet, or a full sized planet I'm merely far away from?

How would you measure the distance between you and the image for reference? How would you measure the width of the object? And more, how do you measure the spatial dimensions of the field of mind that the object appears in. Does it have one at all?