Hold the left mouse button down as you drag the Slider control (labelled "Set Fade Level") below the image (or click on the arrow buttons) to fade between the "pre-Sandy" (31 August 2012) and "post-Sandy" (01 November 2012) Suomi NPP VIIRS 0.7 micrometer Day/Night Band imagery. McIDAS-V images created by William Straka, CIMSS.