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Watermark checks

SynthID Watermark Checker and Detector

Use this SynthID detector when an image may carry an invisible watermark from OpenAI or Google/Gemini image generation. Slop or Not supports SynthID checks for signals embedded directly into the image, compares signed or editable metadata with visual evidence, and keeps online uploads away from outside AI providers. SynthID is not easy to remove, but heavy edits can still make a check inconclusive.

  • You can testPhotos, screenshots, product images, receipts, and profile pictures up to 8 MB.
  • ResultA probability verdict, AI score, and source details when the file carries them.
  • PrivacyDeleted the moment the check finishes. We never keep your photo.

AI detection is probabilistic. Results can vary with new AI models and evasion methods. A real photo edited with AI tools can be flagged as AI.

Online checks are deleted after processing.

What it checks

Check OpenAI and Google Images for SynthID Watermark Signals

SynthID watermark evidence from supported OpenAI and Google/Gemini images

Generator clues from surrounding C2PA or IPTC provenance fields

Fallback image-model score when no readable signal remains

Good Uses

  • Checking a suspected OpenAI, Gemini, or Google-generated image
  • Testing whether an exported image still carries watermark evidence
  • Explaining why provenance and visual detection can disagree

Limits to Know

  • OpenAI and Gemini public verifiers are provider specific, not universal SynthID checks
  • Heavy edits, severe recompression, or very small images can still make a check inconclusive
  • A missing readable signal is not a clean bill of authenticity

FAQ

SynthID Watermark Checker Questions

Is SynthID the same as C2PA?

No. SynthID is an invisible watermark embedded into generated media. C2PA is signed Content Credentials metadata. Slop or Not checks both when the file exposes them.

Why can a SynthID check be inconclusive?

SynthID is embedded directly into the image, but repeated heavy edits, severe recompression, or too little image detail can weaken the signal. The image detector can still provide a probability when the watermark read is inconclusive.

Should Gemini images use this checker?

Use the Gemini detector when Google generation is the question. Use the SynthID detector when the question is specifically about invisible watermark evidence from supported providers.

Related checks

Compare Related Detector Workflows

Gemini AI Image Detector

Check whether a photo may come from Gemini image generation. Slop or Not reads Google SynthID plus C2PA/IPTC metadata, then checks the pixels.

AI Watermark Detector

Use this AI watermark detector to check images for SynthID, C2PA Content Credentials, and IPTC metadata before pixel detection.

C2PA Detector

Use this C2PA detector to check Content Credentials with Slop or Not. It reads signed provenance, then checks pixels when credentials are absent.