I made this picture for an egg on a texture I'm making for Yoshi. I indexed it with 2 colors only for complete simplicity. Pink and White. Every time I remake the texture, the egg either still has green spots, or becomes green with dark green spots :o! HELP MEH!
Eternal Yoshi can answer your Egg problems, he make some great Yoshi Camouflage Textures.
The answer can be found Here---> http://forums.kc-mm.com/index.php?topic=354.0
Scroll down near the bottom of his main post on the front page and he'll explain how the eggshell mechanics work.
I don't see any difficulty in making Yoshi egg texture >.> I have done it before and had no problems with it. IIRC the pallet had 14 or 16 or something like that. Just draw your colors, index it, ASH. Its just like any other texture.
I actually LOOKED for his help. I followed his directions and...I got something that looked like a bad egg (from pokemon 0_o')