Frame optimization is based on overlaying a smaller sub-image rather than a complete overlay of the whole image. This obviously produces a smaller number of pixels and thus a smaller file on disk, to being sent across the network. Also overlaying a smaller frame means the client computer does not have to do as much work in changing pixels on screen. However there are different disposal methods available in the GIF format to handle the last frame displayed, and that can result in different size overlays. Not only that but it is possible to split up the overlays into multiple parts, or update actions, bring about a more complex but more optimized animation.
Frame Optimization Method Comparison
Fig. 19: Min. Bounding Rectangle
Fig. 20: Frame differencing
Fig. 21: LZW optimization
Of course, if you have Web access you can follow the instructions above
except leave your animation full-frame. Browse on over to
http://www.gifwizard.com and run it
through. GIF Wizard automatically does:
Minimum bounding rectangle crop
Frame difference (saves only pixels that change)
LZW optimization (equalizes pixel patterns for better compression)
all in one pass.
GIF Wizard Tips
Page at a time
In addition to optimizing GIFs off the Web or your hard drive, you can
optimize an entire page at a time. Just type in the URL of the page you want
optimized and it'll shrink all your GIFs!
Run it twice
GIF Wizard adds a comment block if it shrinks your file by more than 2%
or 200 bytes. To remove this block just run it a second time.