When someone starts picturing something unusual we say “oh, what an imagination”. Imagination is what is commonly known as creation of images or ideas that have not existed before.
In my personal opinion there is no such a thing as imagination: I belive that everything already exists somehow somewhere…I can back up this idea either with Socrates’s Allegory of The Cave or with the modern string theory -no matter what I take, it is obvious to me that there is noting in the world that has not been existing somewhere yet.
Let’s take horror films, all these dreadful images are nothing else than already existing beings. They definitely exist in our collective subconscious (the prove is that in many different cultures these images are similar), and the collective subconscious is a reality. This reality hunts us in our dreams or drunkard/under drugs state. And this is not imagination, this is pretty real. A good example – Hieronymus Bosch. or just any horror film 🙂