Is it Possible to Import Textures into .bch Files Without Significant Quality Loss? (FE: Fates)

So, I've been attempting to insert custom sprites into Fire Emblem Fates as of late. The character sprites are saved as textures (.png's, it seems?) in .bch files. I've been using Ohana 3DS to do this. However, I've recently learned (and seen in-game) that when the texture is imported into Ohana, it becomes compressed in ways that corrupt the quality of the sprite. For example, I tried to import a custom short-haired sprite for Lucina. It loaded up in-game, but the reduced quality and...

Is it Possible to Import Textures into .bch Files Without Significant Quality Loss? (FE: Fates)