A clear answer. Here’s how.
Uses Floyd–Steinberg error diffusion of weighted RGB luma, scanning left to right/top to bottom. Quantises to black/white at 128 and sends error 7/16 right, 3/16 down-left, 5/16 down and 1/16 down-right. Alpha is retained; hidden RGB can influence nearby error. Output is a PNG, not a hardware-specific one-bit file format. Supports PNG/JPEG/WebP up to 10 MB and 4 million decoded pixels per file. Browser decoding and single-frame PNG re-encoding remove source metadata/colour profiles; no files leave this device.