SynthID Detector: Check AI Images for Google's Watermark
SynthID is Google DeepMind's invisible watermark, woven into the pixels of AI images from Gemini, Nano Banana, Imagen — and present alongside C2PA on ChatGPT images too. It's designed so only the issuer's own detector can read it back, which is why no honest third-party tool can "scan for SynthID" on its own. This SynthID detector does the part it can prove — reading the file for a C2PA Content Credentials manifest instantly in your browser — and then hands you to the official provenance checker to confirm SynthID itself, step by step. If the image is watermarked, you proceed straight to the SynthID remover to clean both the pixel signal and the C2PA layer.
Why a 'SynthID Scanner' Can't Be Instant
SynthID embeds a statistical pattern across an image's pixels that its detector model is trained to recognize. By design, that pattern can't be read by anyone without the model — so any browser widget claiming to instantly "detect SynthID" is really just checking metadata and relabeling it. We don't do that. This tool is explicit about the boundary: C2PA we read ourselves; SynthID we verify through the official checker, because that's the only place a real answer comes from.
The Honest Two-Step Check
First, the detector reads your file for a C2PA manifest. If it's there, the image is provably AI-generated and you can clean it immediately. If C2PA is clear, that's not the end — a Gemini or ChatGPT image can still carry SynthID in the pixels. The tool opens the official content-provenance checker, you upload the same image there, and if it reports an AI watermark you come back and proceed to clean. Two layers, each checked where it can actually be confirmed.
Removing SynthID Once Confirmed
Confirmed SynthID needs frequency-domain cleaning, not a metadata wipe — the signal lives in the pixels and survives crops, screenshots and re-saving. The remover this detector routes to disrupts that signal where it lives and strips the C2PA manifest in the same pass, returning a clean file with no visible change. Which AI images carry SynthID: Gemini (including Nano Banana / Nano Banana Pro), Imagen, and ChatGPT stills.