Your computer and camera are designed to be able to enhance the mirage to varying degrees, this is really for aesthetics, they only make the illusion more colourful more contrasted, brighter, it is artificial enhancement,m the technology has been designed that way, many pictures can be enhanced to appear quite beautiful and interesting with vivid colours, much astrophotography is really just abstract art rather then an accurate depiction of astronomical phenomena.
I always aim to take my pictures in such a way as to make them the most accurate depictions of astronomical objects that I can make; every picture, astronomy or otherwise, is a depiction that differs from what your eye would see to varying degrees. Simply doing a longer exposure can make a picture brighter, but that doesn't make it a "simulated image."
My explaination is consistant.
No, you now have two very different explanations.
They don't often appear as perfect round dots.
If my tracking and optics were perfect, they would. Stars always the same shape as the other stars around the same area, and when the tracking works properly they're always perfect little dots. Meanwhile, spectra reveal that the stars are made of various elements such as hydrogen, helium, and carbon, but never water ice.
Well the images would and do assume consistant shapes.
There's no reason at all why they would form spiral structures if it were some refractive illusion. Furthermore, there's absolutely no evidence of any gravitational or other lensing in any of the images I've presented.