To return to the forecast exercise, or wherever you were, hit the back button on your browser. If that doesn't work, try closing this window. Satellite Imagery Satellites take pictures of clouds that move across the earth, usually from a Geostationary Orbit, about 22,500 miles in space. Visible imagery looks at the sunlight reflected off the earth and its atmosphere.
Clouds reflect sunlight well and so show up bright on the visible imagery.
But be careful, so do other things that reflect sunlight well, like Desserts and water. Also, visible imagery is pretty useless when the sun is on the other side of the from the Satellite. IR imagery is based on the Infrared radiation emitted by all objects. Warm objects emit more IR than cold objects. So, IR can be used to figure out how high the cloud is.