old_contents: import sensor, time
  sensor.set_pixformat(sensor.GRAYSCALE)
  sensor.snapshot().save("0:/test.ppm", subimage=(0, 0, 10,10))
  
new_contents: import sensor, time
  sensor.set_framesize(sensor.QCIF)
  sensor.set_pixformat(sensor.RGB565)
  sensor.snapshot().save("1:/test.ppm")
  
subject: Update write image example