Impossible Image- Thoughts

For me it is still incredible that photographic imagery can be created outside of the camera. What can one create without using the camera? What sort of imagery could I produce that requires additional steps within the computer and its software?

I am very interested in the scanner as a way of making digital work. In a sense, the scanner is just a larger camera, but its process requires a computer and some kind of software to reach the desired product. Therefore, if the scanner is necessity to your process of creating the work, then I suppose what ever comes out of that process is "an impossible image.?" Honestly, I am very confused and bamboozled by this concept.