You need to post code, not images of code, for anyone to help you in a meaningful way.
MMA displays the image in a size that it computes will fit in the window. It processes the full resolution. To set the display size of an image, use ImageSize. For example, in your code (which I can't copy to show you) you can do something like
Show[binImg, ImageSize->{1920,1080}]
or
scale = 2; Show[binImg, ImageSize->{1920/scale,1080/scale}]
Regards
