Microsoft Paint and Photos apps add invisible watermark to AI-generated content — developer reverse engineers GUID embedding
A developer has uncovered some previously unknown GUID watermarking functionality deep within Microsoft’s Paint and Photos apps.
Microsoft's Paint and Photos applications have been found to incorporate invisible watermarks into AI-generated content. Developer Xusheng Li discovered this functionality, which involves a GUID watermark that identifies imagery where AI has played a role in creation. This watermark is distinct from a recent controversy surrounding Microsoft's GDID traceable device-specific telemetry.
Li's curiosity led him to investigate the AI features within Paint, and he uncovered watermarker.dll, which is responsible for embedding both visible and invisible watermarks. The invisible watermarking function, WmkWriteWatermark, is called to add the watermark, and if this process fails, Paint aborts the image generation. Additionally, C2PA Content Credentials are attached to the saved file, residing in ProvenanceHelper.dll and backed by provenancesdk.dll.
This watermarking mechanism is mandatory, even on devices where local image generation occurs, as the prompt is still sent to Microsoft servers for moderation. The embedded watermark is believed to comply with Article 50 of the EU AI Act, which requires detectable, machine-readable marks on AI-generated content since August 2, 2026.
Written by urgent.news from Tom's Hardware's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
This story
This is one outlet's version. Read the fullest account.
