Microsoft Paint Embeds Invisible GUID Watermarks in Local AI Images
jedisct1 · x · 2026-08-25
Reverse engineering reveals that Microsoft Paint and Photos embed a server-issued GUID into the pixels of locally generated AI images as an invisible watermark. Although generation is local on Copilot+ PCs, prompts are sent remotely for moderation, and the returned GUID is embedded into the final image. This invisible watermark is separate from visible watermark settings and restricts file formats to C2PA-preserving types like PNG and JPEG.
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