Hold the left mouse button down as you drag the Slider control (labelled "Set Fade Level") above the image (or click on the arrow buttons) to fade between the GOES-12 visible channel image and the corresponding 6.5 micrometer "water vapor" channel image at 22:02 UTC on 06 April 2003. To zoom, click on the "Zoom" button, and then click the "hand" cursor on the image where you want to center the zoom. To toggle between the 2 images, click in the middle of the grey Slider control area, beneath the word "Fade" in "Set Fade Level".