[RM2K3] OFFICIAL RELEASE - QUESTION ABOUT CHARACTER SPRITE SIZE

I've searched for this and I haven't found an answer anywhere. I'm trying to make my game look like the old NES RPGs. I know that each frame in a character's sprite sheet is 24x32 pixels. My question is, does a sprite have to come close to filling that 24x32 box or can it be smaller? Will having a smaller sprite make collisions look odd or something?

Thanks!