Adobe 38040334 - Dreamweaver CS3 User Manual page 388

Allows you to set the image's background. You can maintain the transparency of a 32-bpc (bits per channel)
Matte
PNG by clicking the transparency icon in the Matte dialog box. You can also use Matte to anti-alias soft-edged
objects that lie directly above the canvas by matching the matte color to the target background.
Specifies the image size, in kilobytes. For 8-bpc images, the wizard attempts to achieve the
Optimize to Size
requested file size by adjusting the number of colors or dithering.
GIF and PNG image options
In the Options tab, you can set a transparency value for individual colors in GIF and 8-bpc PNG images so that the
background of the web page is visible through areas with those colors. Do this by adjusting the color palette on the
left of the Options tab. PNG images that have 32-bpc format automatically contain transparency, though you won't
see a transparency option for 32-bpc PNGs in the Optimize panel.
Set to Adaptive by default.
Palette
Set to 0 by default. Not applicable to 8-bpc PNG images.
Loss
Approximates colors not in the current palette by alternating similar-colored pixels so that they appear to
Dither
blend to the missing color. Dithering is especially helpful when exporting images with complex blends or gradients,
or when exporting photographic images to an 8-bpc graphic format such as GIF. Not selected by default.
Note: Dithering can greatly increase file size.
Set to 256 by default. The number of colors is dependent on the current behavior of the
Number Of Colors List
palette. For example, the "Web 216" palette only displays 216 colors.
The display of colors varies depending on the selected palette behavior and maximum number of
Color Palette
colors.
Click on any pixel in the palette and then click on these icons to change, add, or delete color, or to make
Palette Tools
a color transparent, web safe, or locked.
Select Transparency Color Icons
choose the Select Transparency Color option, you can click on any pixel in the palette or on a point of color in the
preview panel to render it transparent.
Allows you to set index, alpha, or no transparency. A gray-and-white checkerboard on
Transparency Pop-Up Menu
document previews denotes transparent areas. To see how your choices affect the image, choose 2-up or 4-up in the
image preview and click on an image other than the original.
•
Use index transparency when exporting GIF images that contain transparent areas. With index trans-
Index
parency, you set specific colors to be transparent upon export. Index transparency turns on or turns off pixels with
specific color values.
•
Use alpha transparency when exporting 8-bpc PNG images that contain transparent areas. Alpha trans-
Alpha
parency allows gradient transparency and semi-opaque pixels.
Lets you set the image's background. You can maintain the transparency of a 32-bpc PNG by clicking the
Matte
transparency icon in the Matte dialog box. You can also use Matte to anti-alias soft-edged objects that lie directly
above the canvas by matching the matte color to the target background.
Reduces file size by removing colors not used in the image.
Remove Unused Colors
Displays an interlaced image initially at low resolution and progressively increases to full
Interlaced Browser Display
resolution during download. Not selected by default.
Lets you specify a size, in kilobytes, for the image. For 8-bpc images, the wizard attempts to achieve
Optimize To Size
the requested file size by adjusting the number of colors or dithering.
These buttons allow you to select, add, or remove a palette color. For example, if you
September 4, 2007
DREAMWEAVER CS3 381
User Guide