The images are updated once an hour at 50 after the hour. This image is the equivalent of taking a black and white photo of the earth. The bright areas show where the sun is being reflected back into space as a result of clouds or snow cover. Clouds and snow show up white. The thicker the cloud, the brighter the color.
Land surfaces show up as gray and ocean surfaces nearly black.
The major limitation to visible imagery is that it is only valid during daylight. East - GOES east view centered over 75 west longitude showing eastern US and Atlantic Ocean. West - GOES west view centered over 125 west longitude showing western US and Pacific Ocean. US - this is a pieced view of GOES east and west remapped to a polar stereographic projection. Regional - these are regional views remapped to a polar stereographic projection.