Now that you've created an optimized global palette it's time to optimize
your frames. If you have access to GIFWizard you can skip this step. Using
Debabelizer's "compare" feature, calculate the difference (the pixels that have
changed) between each frame (i.e., frame 1 and 2 = 2d). Open the first frame and
select Misc | Compare, select the next frame and Debabelizer finds only the
pixels that have changed between these two frames; see Figure 14. Set the
compare options to change unchanged pixels to your key color, so you can drop it
out later using GIFBuilder's transparency feature. Save the frame uncropped.
Figure 14 - Debabelizer's compare feature in action
