I may well have asked this before, but if so I either have forgotten or don't remember the answer. If so, my apologies.
I have a mental block about resolution.
As I understand it, resolution is essentially the density of pixels per square whatever. Therefore if a square inch contains 500,000 pixels it will be much clearer and sharper (i.e. higher resolution) than a similar square containing only 250,000 pixels.
Now ... if that is correct, what happens in the following scenario. I photograph a chess board at two different resolutions. I process them both on the PC and on the lower resolution image I cut out one of the squares. I copy a square from the higher resolution image and place it in the place of the removed square and then merge that image into one. What happens to that image? Does it have 63 squares all with 250,000 pixels - plus one square with 500,000 pixels? If not, why not?