► Note 125

In the case of Figure 10-5, there were only three colors in the palette even though the default setting I initially used specified 32. This is good—it means the program is not leaving unnecessary colors in the palette, which would inflate the file size. In this image, there are indeed only three colors needed.

If your image looks good with 32 colors, try reducing the number of colors in the color palette as low as you can go without severely compromising the image's quality. If it looks terrible with 32 colors, increase the number of colors a little bit to try and gain back some quality. Don't go too high too quickly, though, because each color you add into the file increases its size. In my experience, few GIF files need more than 32 colors to be successful.

Aside from the number of colors, edit the remaining settings as needed:

• For "Lossy" identify the lossiness level; higher numbers make smaller file sizes but reduce image quality (not available for interlaced GIFs or when Noise or Pattern dithering is used).

• Specify whether to use dithering to reduce banding between colors. (For more information on dithering, see the tip "Use Dithering to Smooth Edges in GIF and PNG-8 Files.") When dithering is used, specify the amount of dither; the higher the percentage, the larger the file size.

• Specify whether the file should be interlaced.

• For "Matte" identify color of web page background when portions of the image will be made transparent.

• For "Web Snap" specify the number of colors you want to force to be web safe.

• Select "Transparency" to specify that the file contains transparent areas. If it does, use the menu below to dither the semi-transparent pixels. (Techniques using the transparency options can be found in the tip "Optimize Transparent Web Graphics.")

• For details on the small circle inside of a rectangle found next to three options in the Settings menu, see "Use Weighted Optimization."

When you're finished, in Photoshop click Save to save the slice or file using the selected optimization settings. (To save your settings without actually saving the slice or file, click Done to return to the main Photoshop window.) In ImageReady choose File I Save Optimized or Save Optimized As.

Slice being optimized

Slice being optimized

Figure 10-5 When optimizing GIFs, I like to start with the default GIF setting named GIF 32 Dithered.

Figure 10-5 When optimizing GIFs, I like to start with the default GIF setting named GIF 32 Dithered.

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