After image is not made by going the speed of light, holy crap.
It's a visual effect from moving faster than your opponents brain can compensate leaving a ghosted image, ideally the person using combat teleport would need a few moments to realize you're not there anymore before warping.
I think maybe you are thinking of the flash who leaves a trail, or an image that keeps moving like what Goku did to Cell during the Cell games. That is a different technique which uses Ki to create and extend the after image, it's also used for multiple after images which you could have run in many different directions all at the same time.
Edit: I should also mention that people who use combat teleportation would also leave an after image, as the premise is the same as using the afterimage technique.
It's a visual effect from moving faster than your opponents brain can compensate leaving a ghosted image, ideally the person using combat teleport would need a few moments to realize you're not there anymore before warping.
I think maybe you are thinking of the flash who leaves a trail, or an image that keeps moving like what Goku did to Cell during the Cell games. That is a different technique which uses Ki to create and extend the after image, it's also used for multiple after images which you could have run in many different directions all at the same time.
Edit: I should also mention that people who use combat teleportation would also leave an after image, as the premise is the same as using the afterimage technique.