Appendix Iii: Creating Compact Animations - Ulead GIF ANIMATOR 4.0 User Manual

Appendix III: Creating compact animations

There are three ways you can significantly reduce the size of your animated GIF files: reduce
the color palettes, reduce the number of image layers, and optimize the individual image layers.
There are pros and cons to using the first two methods, and they should be implemented
judiciously. Keep in mind that the goal of creating animated GIF files is NOT to make them as
compact as possible - creating compelling animations for the web is. However, until data
transmission speeds increase and everyone on the net has faster access, file size should still be
a significant consideration when composing your animation.
The best way to reduce color palettes is to use the Global Palette as often as possible for
displaying the colors of individual layers. If one or more layers have slightly different colors
included in their palettes, set your General Preferences to accumulate new colors. This way
you needn't create a Local Palette for a layer that varies only by a few colors from the rest. If
a layer has radically different colors from the others in the animation, your best bet is to give it
a Local Palette and then reduce it by removing the colors that it shares with the Global Palette.
Otherwise, the image may not display properly. The best reduced palettes are 16-, 32-, 64-,
and 128-color palettes.
The second method of reducing the file size of your animation is to delete any unnecessary
layers. In some cases, this may not be desirable due to the adverse affects it may have on the
quality of your animation. But if you can get away with cutting out a few layers here and there
then you should do it.
Ulead GIF Animator allows you to greatly reduce the file sizes of the individual layers through
a third method: optimization. When you select the File: Optimization Wizard command, GIF
Animator analyzes the image layers in your animation, compares them with one another, and
then removes all the redundant pixels that the layers share with one another. In some cases,
this method can reduce your overall file size by as much as 200%.
Finally, you should consider image layer sizes. If the motion of the animation occurs within a
smaller field than the size of the "backdrop", then you shouldn't necessarily use image layers
that are the same size as your background. With GIF animations, you can easily overlap much
smaller GIFs to create small areas of animation set against a static backdrop. This will reduce
your file size considerably, but again, do this only if the quality of your animation doesn't
suffer as a result.
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