I'm not aphantasic (I'm hypophantasic) but I can understand! Maybe it's a book without pictures (y'all can 'see' descriptions but not the image) a foggy mirror, or a locked gallery (the memories to the images exist, but you can't see them) May be irrelevant because I personally don't experience it, but good luck! Trying to make people understand is hard (especially millennial parents like mine ngl)