2 => this.DecodeUpFilter(scanline, previousScanline), 3 => this.DecodeAverageFilter(scanline, previousScanline, bytesPerPixel),
4 => this.DecodePaethFilter(scanline, previousScanline, bytesPerPixel),
0 => scanline, // Skip filterType byte 1 => this.DecodeSubFilter(scanline, bytesPerPixel), 2 => this.DecodeUpFilter(scanline, previousScanline),