Now on the Chrome Web Store

Install it on your computer.

One click from the Chrome Web Store. It updates itself from then on, which the manual version below never did.

Add to Chrome — free

Chrome or Edge, on Windows or Mac. Not phones. No account, no card.

Then pin it, or you will not see it again.

Chrome hides new extensions behind the puzzle piece icon to the right of the address bar, and it will not let us change that. Click the puzzle piece, find ImposterShield in the list, and click the pin beside it. The shield then sits in your toolbar and changes color on every page you visit. Hidden, it cannot tell you anything.

The manual way, if you need it

You almost certainly do not. Use the button above. This is here for anyone on a locked-down work laptop that blocks the Chrome Web Store, or who wants to read every file before running it. A manual install never auto-updates, so you would have to redo these steps for each new version.

Download the extension (5 MB)

  1. Unzip the file you downloaded

    Right click it, choose Extract All, and note where the folder lands. Keep that folder. Chrome runs the extension out of it, so deleting it later removes the extension.

  2. Open your extensions page

    Chrome will not let a website link you here, so you have to paste it yourself.

    chrome://extensions

    Paste it in the address bar and press Enter. On Edge use edge://extensions.

  3. Flip on "Developer mode"

    Top right of that page. It sounds alarming and it is not. It is simply the switch that lets you install something that has not come from the Chrome store, which is where we are until our review clears.

  4. Click "Load unpacked" and choose that folder

    The button appears top left once Developer mode is on. Select the folder itself, not a file inside it. The right one is the folder containing manifest.json.

Last thing: pin it. Click the puzzle piece icon beside the address bar, find ImposterShield, and click the pin so the shield stays visible. If it is hidden it cannot tell you anything.
One more download happens by itself, once. The first time it runs, the extension fetches its detector model (about 23 MB; versions before 0.12.5 used a 90 MB file) and keeps it. Everything that reads proof out of a file works the second it is loaded, and the detector joins in when that download finishes. Nothing you browse is ever sent to us. The one other request it makes is to Vecteezy or Pixabay, for a search result that comes from them, to read whether that site labels the picture AI-generated. That request carries the picture's page address only, with no cookies. The privacy policy has the details.

Reading the shield

The icon changes color based on what is on the page you are looking at. Click it any time to see what it found.

GreenWe checked and saw no signs of AI. On a video, the frames we looked at came back clean. It is not a promise that something is real.

YellowSome sign of AI: one image carries an AI signature, the page says so itself, our detector thinks a picture looks AI-made, or some of a video's frames or its caption lean that way.

RedA strong sign of AI: two or more images carry AI signatures, the platform has labelled the video as AI, the video shows an AI tool's logo, or our detector was sure about several of its frames. The popup tells you which.

On Google and Bing, it checks where each result came from. The search engine shows you its own rebuilt copy of every picture, and that rebuild throws the AI marker away. So on image results, and on the pictures beside ordinary results and ads, the shield looks at the site each one comes from. A picture from an AI image generator site gets outlined. So does one from Vecteezy or Pixabay when that site itself labels it AI-generated, because those sites make the people who upload declare it. And when a result points at an original file our detector can reach, it fetches that full-size picture and takes its own look: one that looks AI-generated gets a dashed outline and can turn the shield yellow, never red, because a judgment is not proof. Everything else it cannot vouch for either way, so a page of those results stays gray, not green. Social feeds rebuild pictures the same way, with nowhere to look them up, so they stay gray too. Open a picture at its original source to get a real answer.
Videos get checked too. On YouTube Shorts, TikTok, Instagram Reels and Facebook videos the shield reads the platform's own AI label, looks for the logo AI video tools stamp on what they make, and runs a few frames of the video you are watching through our detector. It stays gray for the first few seconds while it watches, then turns red, yellow or green. Green means the frames it checked looked clean, not that the video is guaranteed real.
Proof and judgment look different, on purpose. A solid outline means the file itself carries an AI marker: a Content Credentials stamp, or the tag Midjourney and Stable Diffusion write into what they make. That is proof. A dashed orange outline marked "Likely AI" is our on-device detector's judgment of a full-size picture whose file carries no marker. It is never counted as proof, and on a single picture it can turn the shield yellow but never red. On a video, where it looks at several frames, being sure about more than one of them turns the shield red. Either way it does not show you a percentage. We tuned it to stay quiet, and we measure that on real photographs before every change: on a bench of 381 real photos, heavy on the polished stock style that fools detectors, it wrongly flags about 1 in 200, and about 1 in 150 real video frames. In return it catches roughly a quarter to a third of current AI images that carry no marker at all, more from older generators, fewer from the very newest such as GPT-4o's images and Flux. Most yellow flags you see will be right, most AI will still get past it, and the occasional real photo will be flagged wrongly; the popup says all of that out loud. It skips small pictures entirely, because nothing that small can be judged honestly. Two earlier detectors called most real photographs AI, so we switched them off; this one replaced them only after beating them on exactly that test.

Try it

Visit the test page. It holds the same photograph four times: three carry AI markers and one does not. The shield should turn red, report three, outline those three, and leave the fourth alone. If it stays green after the page finishes loading, the extension is not working and we want to know.

Also free: the computer scan

The extension covers what you see in your browser. The scan covers the machine itself, and tells you whether anything on it can watch your screen or be controlled from somewhere else. Windows only, nothing installed.

Something wrong?

Write to [email protected]. Tell us the page you were on and what color the shield was. That is genuinely the most useful thing you can send.