Question about iOS sprites.

Good morning, Tigsource.

I've spent the last few days creating sprites for an Android/iOS game. The game will be a drag-and drop type.
I read somewhere that I have to make sure all iOS sprite images should have dimensions divisible by 4.

I have a few questions about this:

1. Do they have to be divisible by 4 both sides? For example, a 64 x 64 image would obviously work but will a 64 x 33 or any odd number work?

2. For animations, I thought of making the body parts separate to be able to add animations in-game. Is this a good idea or should I save them in a 4x4 divisible document size and convert them into GIF?

3. I have images that are (odd # x odd #). Will it work for iOS if I just multiply the drawing x4 so that the resulting sprite is divisible by 4?

Thanks!