Yes, 0.1mm would be much better, that's 254 DPI. You'd also want 24 bits (3 bytes) per pixel instead of 1 bit. That gives you 0.43x0.43 miles, which is still mighty impressive.
how long to walk that distance, VS how long to read the image from the SD card......
answer:
walking the perimeter (aprox 2 miles): aprox 30min
reading 1tb (assuming sustained speed of 20mb/sec): 14.5hrs
next: consider WRITE speed...
so, 1h 44 minutes, which is not that bad
The sd cards I have always list some performance like "up to 80mb/sec" but never seem to get close in reality.
Ahh, the days before "retina displays", yes.
;-)