This is an image composed of 4 CGs from Fate/stay night PC combined together.

First I took the full zoomed-out CG and upscaled it to 2400x1800. I then took the first of the three zoomed-in CGs and upscaled it to 1133x850 (I left the latter two zoomed-in CGs alone). Then I put all three zoomed-in CGs each into their own layer and assembled them on top of the upscaled zoomed-out CG. The first and the third zoomed-in CGs overlap a bit, and since the first was upscaled some, I layed the 3rd one on top of the 1st. Finally I added 10 pixels of "fading out" to all the boarders of each zoomed-in CG layer.

FYI, the two bits of upscaling were done via S-Spline Max set to "downsize"