More of a Game Graphics than a mechanics question

You have to realise there is a team of artists devoted to things like this. Also Nexon AM takes a lot of their stuff from Korea. So I wouldn't say highly unlikely, more highly likely that they duplicate each sprite, adjust it to the angle/state they need it in and then clean it up by hand.

I'm well aware that the art in Maplestory is done by more than one person, but efficiency is still efficiency.