Reverse engineering reveals how Paint and Photos embed a server-issued GUID into the pixels of locally generated AI images. 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 invi...