I guess if you are talking about how Minish Cap sprites use a black border around them, then I understand what you are getting at. The black border though was altered to a higher shade of green than the background so that it would blend in with the background. If I had just used the raw kinstone rips, its black border would look jagged because of how it would be displayed by itself. I had tried to add shading around the raw rips black border (namely where the color parts of the sprite make contact with the background), but the jaggedy look was not reduced that much and in some attempts it was made worse.
I don't know, it is probably because I am bad at making edits, if someone could make it work though with a black border, I'd consider replacing the current images though.