On naturalism and consciousness

[Angrboda]

Here's a thought experiment.

Let's say that on the desk in front of me is a small porcelain rocking horse, about 6" tall. In my mind's eye is an image of just such a rocking horse on just such a desk. However, there are multiple ways this image could have gotten into my mind.

1. the image of the horse could have been relayed from my eyes;
   
2. I could have simply imagined the horse with no prior experience of it;
   
3. a genius neurosurgeon could have figured out the encoding of my memory and surgically implanted the memory of it;
   
4. I could have hallucinated the image of it.

In which of these cases is the image in my mind "about" the rocking horse on my desk and why? The image in my mind is the same in all four cases. Assuming that you picked #1 as being "about" the rocking horse on my desk, what makes that image "about" the rocking horse when the others are not? Or if none or all of them are "about" the rocking horse on my desk, what makes it so?