The US regional images are available for 19 regions plus a CONUS view. There are four types of images:
Visible images are shown in a gray shading where brightness shows the amount of sunlight reflected back. Values run from 0 to 100.
Gray scale IR images show surface temperature values whether it be the ocean, land or a cloud. The scale shows temperature values starting at -70C (white) and going to 30C (black).
This is similar to the gray scale image except it uses a rainbow style color table starting at magenta (-70C) to blue (-45C) to green (-20C) to yellow (-5C) to orange (5C) to red (20C).
Even though the water vapor channel is in the infrared and thus returns a temperature value. But typcally the WV values relate to the depth into the atmosphere until you hit water vapor. Greens are blue show high clouds whereas dark gray and red are near ground surface.
The images are generated every 30 minutes and can be looped.
The international images are presented for 12 ICAO regions. There are just two types of images: infrared gray and infrared color. Some regions are updated every 30 minutes. Regions that contain Europe are restricted to every 6 hours by international agreement. By default, the latest image is shown but older images can be displayed through an animated loop.