I have extreme aphantasia. Everything is black when I close my eyes. The only sense that I can realistically imagine is sound, and yes, I do "hear" a song "stuck in my head". The name for that is an "earworm". My wife has hyperphantasia. When she imagines something, she is fully there. Sights, sounds, smells, touch. She says it's as real as real life. When she needs to spell a word, she apparently actually sees the letters floating in front of her open eyes. When I said that I don't see that, she said, "How can you spell?", with some alarm in her voice. She also doesn't understand how I can remember visual images, if I can't see them. I think I store memories as linked concepts. For example, I can clearly remember the house I grew up in: Two stories, red bricks, dark green shutters, white trim, etc. even though I can't actually see anything in my "mind's eye". Sometimes she says she sometimes wishes she had aphantasia too, because when she remembers something bad from her life (usually in dreams), she relives those traumatic events as if she is really there.