This is a picture of Jupiter taken in infrared light. The amount of infrared light tells you something about the heat being radiated into space by Jupiter. Jupiter actually emits twice as much energy as it receives from the Sun, indicating that it has some type of internal energy source. In the picture you can see places where a lot of infrared radiation is given off by Jupiter (bright white in the picture) and then other places where something is keeping the radiation from reaching us. These places appear black.
If you look at Jupiter in visible light, you will see that Jupiter is covered by clouds arranged in bands. The cloud bands that you see on Jupiter block the infrared radiation from leaving the planet. Holes in the clouds let heat through from the deeper and hotter parts of Jupiter's atmosphere.
Click on the picture. This picture shows Jupiter in infrared light and next to Jupiter two people whose pictures were also taken in infrared light. The parts of the people not covered by clothes are radiating a lot more infrared than those parts covered by clothes. The clothes on the people and the clouds on Jupiter both block the infrared radiation.