Netscape Navigator uses a 216-color palette (a 6x6x6 color cube) on Microsoft Windows 3.1, 3.11, 95, and NT when your system is running in 8-bit color mode (256 colors on screen). The value for each element of the color -- red, green, and blue -- will always be one of these:
0, 51, 102, 153, 204, 255 (decimal) 00, 33, 66, 99, CC, FF (hexadecimal)Therefore, if you only use the following color values in the images on your web pages, they will display cleanly for people who are using Netscape Navigator on Windows to view your pages. If you use any colors that are not in the following list, then Netscape Navigator on Windows will dither them, sometimes with not very pretty results.
URL: http://mysite.verizon.net/bonniehill/pages.aux/netscape.colors.html