MACROMEDIA FLASH 8-USING FLASH Use Manual page 471

Smooth
applies anti-aliasing to an exported bitmap to produce a higher-quality bitmap
image and improve text display quality. However, smoothing might cause a halo of gray
pixels to appear around an anti-aliased image placed on a colored background, and it
increases the GIF file size. Export an image without smoothing if a halo appears or if
you're placing a GIF transparency on a multicolored background.
Dither Solids applies dithering to solid colors as well as gradients. For more information,
see Dither options in step 8.
Remove Gradients
file to solid colors using the first color in the gradient. Gradients increase the size of a GIF
file and are often poor quality. If you use this option, select the first color of your gradients
carefully to prevent unexpected results.
7. Select one of the following Transparent options to determine the transparency of the
application's background and the way alpha settings are converted to GIF:
Opaque makes the background a solid color.
Transparent makes the background transparent.
Alpha
sets partial transparency. You can enter a Threshold value between 0 and 255. A
lower value results in greater transparency. A value of 128 corresponds to 50%
transparency.
8.
Select a Dither option to specify how pixels of available colors are combined to simulate
colors not available in the current palette. Dithering can improve color quality, but it
increases the file size. Select from the following options:
None
turns off dithering and replaces colors not in the basic color table with the solid
color from the table that most closely approximates the specified color. Turning dithering
off can result in smaller files but unsatisfactory colors.
Ordered
provides good-quality dithering with the smallest increase in file size.
Diffusion
provides the best-quality dithering but increases file size and processing time. It
also works only with the web 216 color palette selected.
9. Select one of the following Palette Types to define the image's color palette:
Web 216 uses the standard 216-color, browser-safe palette to create the GIF image, for
good image quality and the fastest processing on the server.
Adaptive analyzes the colors in the image and creates a unique color table for the selected
GIF file. This option is best for systems displaying thousands or millions of colors; it
creates the most accurate color for the image but increases file size. To reduce the size of a
GIF with an adaptive palette, use the Max Colors option in step 10 to decrease
the number of colors in the palette.
, which is turned off by default, converts all gradient fills in the SWF
Publishing Flash documents 471