The observations were made between 1450 and 1455 UTC on July 26th, 2000. Clouds can be both reflective and transmissive, so thicker clouds are white while thinner clouds are more gray and can be semitransparent. The first image, which shows most of the Greenland continent, was made from a 5-minute segment of the satellite's orbit as it traveled from south to north. The North Pole is near the upper left part of the image. What the second image shows is how fractured the ice is in an area near the pole.
Winds constantly move ice, exposing open water and creating the fractured pattern seen here.