Images from ChatGPT and the OpenAI API carry C2PA Content Credentials naming OpenAI and marking them as AI-generated, plus a SynthID watermark in the pixels. Gemini images carry SynthID and, for newer models, Content Credentials too. Adobe Firefly adds Content Credentials. The credentials disappear when an image is screenshotted or uploaded to most social networks; SynthID usually survives.
At a glance
| Tool | Content Credentials (C2PA) | SynthID watermark | AI label in metadata |
|---|---|---|---|
| ChatGPT and OpenAI API | Yes, issued by OpenAI | Yes, since 2026 | Inside the credentials |
| Gemini app (newer image models) | Yes | Yes | Inside the credentials |
| Adobe Firefly | Yes, applied automatically | No | Inside the credentials |
| Claude (images and SVGs it creates) | Yes, issued by Anthropic | No | Inside the credentials |
| Microsoft Image Creator | Yes, reported since 2023 | No | Inside the credentials |
| Stable Diffusion (local) | Usually not | No | Often the full prompt in PNG text |
What exactly each tool writes can change with new model versions, so check individual files rather than relying on the table alone.
What Content Credentials hold
Content Credentials are a signed record, following the open C2PA standard, attached to the file. For an AI image they typically include:
- The issuer, such as OpenAI or Google, who signed the record.
- The generator, the app or model that made it.
- An action list, for example created with the source type trainedAlgorithmicMedia, the standard way of saying fully AI-generated.
- A timestamp and later edits, if editing apps kept the record going.
Our Content Credentials checker shows whether they're present, who issued them and whether AI is declared. To verify the signature, use verify.contentauthenticity.org.
What SynthID adds
SynthID is a watermark woven into the pixels. You can't see it and it isn't in the metadata, so it survives screenshots, cropping and re-uploads. Google uses it for Gemini images, and OpenAI adds it to ChatGPT images through a partnership with Google. Check for it at synthid.com. More in SynthID explained.
What survives sharing
| What happens to the image | Content Credentials | SynthID |
|---|---|---|
| Downloaded and shared as the original file | Kept | Kept |
| Screenshot | Lost | Usually kept |
| Posted to most social networks | Usually lost | Usually kept |
| Cropped or filtered in a basic editor | Usually lost | Usually kept |
| Edited in an app that supports C2PA | Kept and extended | Usually kept |
This is why a missing label doesn't mean an image is real. It may simply have passed through something that stripped the metadata.