Minimizing GIF File Sizes 281GIFMinimizing GIF File SizesWeb Design in a Nutshell, eMatter Editionget instant feedback on the effects of your settings and choose the best configura-
tion. Settings can be named and saved for future use.
Adobe ImageReady 1.0
The Optimize Palette with GIF selected in the Formats menu (Figure 14-11)
contains all the controls over image optimization.
ImageReady defaults to a Perceptual Palette that is made up of the best colors in
the image by giving priority to the colors for which the human eye has greater
sensitivity. This palette usually produces images with the best image integrity. To
the right of the palette menu is the Colors control where you can select from a list
of standard color-depths (8, 16, 32, etc.) or set it to Auto to capture the exact
number of colors in the image.
Dithering is controlled by a sliding scale from 0 to 100%. Higher numbers result in
more dithering and higher file sizes. Reducing the amount of dithering increases
the efficiency of the LZW compression on the image. As mentioned above, you
need to make the decision at which point the loss in image quality outweighs the
file size savings. The slider makes it possible to make more fine-tuned decisions.
Like other web-specific design tools, ImageReady provides a preview of the image
that reflects the changes of your settings in real time. It also shows the effects of
your changes on the file size and approximate download time. Settings can be
saved as “Droplets” and used for batch processing by dragging and dropping files
onto the Droplet icon.
HVS ColorGIF 2.0 (Digital Frontiers Software)
HVS ColorGIF 2.0 plug-in from Digital Frontiers is in a class by itself when it
comes to GIF optimization. In all the tests I’ve run, HVS ColorGIF’s compression
algorithms produce the smallest GIFs while maintaining the highest image quality
compared to other optimizing tools.
It can be used with Photoshop, ImageReady, Fireworks, Paint Shop Pro, or any
graphics application that supports plug-ins. ColorGIF is available for both Mac and
PC; you can download a demo from Digital Frontier’s web site athttp://www.
digfrontiers.com/.
Figure 14-11: Adobe ImageReady’s Optimize dialog box