Modding Help What's the NPC sprite size limit?

So I wanted to create some mods that edit the sprite sheet of characters (like giving some characters more radical hairdos and whatnot just for fun).
I've been searching the forums and everywhere possible, but I was curious if anyone knew the sprite size limit for regular NPCs (not to be confused with portraits, I mean like standing sprites, walking sprites, etc). I'm just curious on how far I can go with some of the effects (like different types of fantasy wings on some of them would also be a cool concept, if it would fit each sprite).
I'm currently working on one that I messed up on (transparency issue), but I'm not sure that it will fit after I'm finished.

 

The NPC character sprites have a limit of 16x32 for each pose, so there's not a lot of room to work with unfortunately. But it sounds like a fun project

 

Thanks for the answer, I just wanted to make sure before I did anything too crazy.

 

I wonder if there's a way to override the hardcoded limit with a SMAPI mod though.