The simplest type of animation is the flip book. Fundamentally it displays a sequence of images, one after the other. Each image completely covers the previous image. The 5 images shown ABOVE are the frames that make up the first animation (A).
Since the GIF format efficiently compresses large areas of flat color, this process works really well when the background is a solid color, and the object in motion is small and also a solid color.
Increasing the number of frames in the animation, makes it look smoother, but at the cost of additional file size. All of the animations (A --> E) are small because the background is a solid color (black), and the moving item is small and solid colored (white with minor shading).
The final three animations are all repeats of GIF C., but all are running at full speed. They are slightly smaller than the original, but notice that transparency and disposal method have no effect on their size.
The final two may look slightly different depending on the browser that you are using. NetScape does not handle the frame "disposal methods"** properly (version 1-4). The animations are many times faster in NetScape, but may appear incorrect.