heh.. I've never heard about that before, but I'm not surprised.

16 bit is usually either 5 bits of eachs color and 1 alpha (or it's unused), or 565 (6 green).

In 8 bit, each component of each color can have 256 possible values (0-255), which is 8 bits. To fit these 8 bits into 5 or 6 you get rid of the least significant bits. In the case of 5, the last three bits get chopped off, which can be at most 111, or 7. And.. um.. when you're going up by 1, 7 can be a lot.. so.. um.. I dunno. :P

8-bit is paletted, which lets you use any 256 (with the exception of JJ2 colors and whatnot :P) of the colors available in 24bit (8-8-8). Some of them aren't available in 16bit, so sometimes less is more


Or I could be wrong. But I dunno :P