Welcome to Web Witchery, Web Design eZine Optimizing GIF Files Gif files can use up to 256 colors. They often don't use all the colors. You can save space by reducing the number of colors in your file. More often that not, my graphics only use a portion of the 216 color palette. I don't think I have ever created something that used all 216 colors.
Lets use the dragon as an example.
This is the palette for the dragon. He only uses 104 colors out of the 216 in the web palette. He is currently 12k. With the additional unused colors stored in his file, he jumps up to 14k. To reduce the palette in Photoshop, simply save as indexed color, revert back to RGB, then back to index, and save as exact.