A researcher has shown that AI images made in Windows Paint and Photos carry an invisible, server-issued identifier hidden in the pixels, tied to the prompt that produced them. Prompts are sent to Microsoft for screening, and consecutive requests are linked to each other, so the marks could in principle be traced back to an account. Microsoft discloses that it watermarks such images but has not spelled out that the mark is unique per prompt, and it did not comment.
What changed
Microsoft's Paint and Photos documentation disclosed AI watermarking but not that the hidden mark is a unique per-prompt identifier issued by its servers.
What it unlocks
Understanding that images generated in Windows Paint and Photos carry a hidden code that Microsoft could in principle trace back to the prompt and the account behind it.
- 16-byte identifier embedded in pixels
- 190+ AI providers signed EU code
Sources