GIF Images and Bit Depth: Dither

Properties	Image	Palette (adaptive)
8 bit 256 colors 64.9 kb
7 bit 128 colors 52.3 kb
6 bit 64 colors 43.4 kb
5 bit 32 colors 34.7 kb
4 bit 16 colors 26.7 kb
3 bit 8 colors 18.6 kb
2 bit 4 colors 14.2 kb
1 bit 2 colors 5.86 kb