In article ,
wrote:

Normal screen resolution is 1920 x 1080 pixcels.

nope. that's one of *many* display resolutions available today.

If an image is
produced by a sensor with the same resolution, then enough
information, as levels of red, green and blue, ranging from 0 to 255,
are obtained for each of the 1920 x 1080 = 2,073,600 pixcels, and the
image can be displayed accordingly. Now, if the number of sensor
pixcels are doubled in both dirrections, then the image is produced at
a higher resolution, and fully 4 pixcels have to be mapped into each
of the full screen display pixcels. In this case, the 4 should be
resolved into one, using some kind of round off scheme.

what you're describing is a retina display, except that it's a lot more
complicated than simply rounding off and may not be double either.