Microsoft Paint and Photos Embed Server-Issued GUIDs as Invisible Watermarks in Locally-Generated Images

Microsoft's Paint and Photos apps embed server-issued GUIDs as invisible watermarks in locally generated images, with prompt moderation occurring remotely even on Copilot+ PCs where image generation is local. The GUID is added alongside C2PA metadata, and AI-generated images can only be saved in C2PA-preserving formats: PNG, JPEG, GIF, and .paint.

TL;DR Microsoft Paint supports both local and cloud image generation Paint and Photos also ship local AI models The two apps send the prompt to a remote server for moderation The server returns a GUID along with the moderated prompt The GUID is embedded into the locally generated image as an invisible watermark A separate visible-watermark setting does not control this invisible watermark On Copilot+ PCs, image generation is local but prompt moderation remains remote Microsoft discloses that Paint adds C2PA metadata to AI-generated images AI-generated image saves limited to C2PA-preserving formats: PNG, JPEG, GIF, and .paint