Why are you using PNGs as a texture format? Generally, you'll use BC textures for the most part, or barring that, your images will be compressed as part of your

Why are you using PNGs as a texture format? Generally, you'll use BC textures for the most part, or barring that, your images will be compressed as part of your archive format with some sort of super-compression algorithm that compresses the pakfile block-by-block. Perhaps you're referring to your texture compression/conversion pipeline which ingests PNG from your DCC tool of choice?