Removing Unused Colors; Dithering To Approximate Lost Colors; To Dither A Graphic; To Select A Color Depth Beyond 256 Colors - MACROMEDIA FIREWORKS 8-USING FIREWORKS Use Manual

To select a color depth beyond 256 colors:

Select a 24- or 32-bit file format from the Export File Format pop-up menu in the
Optimize panel.
Higher color depths create larger files and are typically not ideal for web graphics.
Use only 24- or 32-bit color depths when exporting or saving photographic images
with continuous tones or complex gradient blends of colors. For high-color-depth
graphics on the web, use JPEG files. For more information, see
on page 346.

Removing unused colors

Removing unused colors from an image before exporting or saving makes its file size smaller.
This option is available only for GIFs and other 8-bit graphic file formats.
To remove unused colors:
Select Remove Unused Colors from the Optimize panel Options menu.
To include all colors in the palette, including colors that are not present in the
exported or saved image:
Deselect Remove Unused Colors.

Dithering to approximate lost colors

Dithering approximates colors not in the current palette by alternating similarly colored
pixels. From a distance, the colors blend to create the appearance of the missing color.
Dithering is especially helpful when exporting images with complex blends or gradients or
when exporting photographic images to an 8-bit graphic file format such as GIF.
Dithering can greatly increase file size.
The dithering option is available only for GIFs, other 8-bit graphic file formats, and
WBMPs.

To dither a graphic:

Enter a percentage value in the Dither text box of the Optimize panel.
"Optimizing JPEGs"
Optimizing in the workspace 339