MS Paint and Photos inivisibly watermark even locally generated output with GUID

Microsoft Paint and Photos embed an invisible watermark containing a server-issued GUID into every AI-generated image; the GUID is returned after remote prompt moderation and added via Watermarker.dll. The apps also ship local ONNX models for image generation, but still rely on remote moderation, and they preserve the watermark only in C2PA-compatible formats such as PNG, JPEG, GIF, and .paint.