Why this is different
There are a dozen AI image detectors. Most work the same way: you upload your picture to their server, a model looks at the pixels, and you get a number back. Here is what happens here instead, and, further down, where that approach is worse.
| Most detectors | SynthCheck | |
|---|---|---|
| Where does your picture go? | To their server, to be processed | Nowhere. It is read on your device |
| What comes back? | A confidence percentage | The evidence found, graded by how much it can carry |
| Can you see how it decides? | No. The model is theirs | Yes. The whole thing is public, and it is the same code your browser runs |
| Signed Content Credentials | Read and repeated, or handed to an uploader | Signature and image binding checked on your device |
| Cost and limits | A few free checks a day, then a subscription | Free, no account, no limit. Nothing is processed on our side to pay for |
| Works with the internet off? | No | Yes, and that is the easiest way to prove nothing is uploaded |
What that costs, in one example
DeepAI’s free AI image detector is among the most used. Its page invites you to upload profile photos, product listings, evidence for legal and insurance claims, and identity documents. The check itself is carried out by a second company, TruthScan, named at the foot of the result.
We also sell Identifiers and User Content to Other Third Parties for their own business and commercial purposes.
That is a sentence from their own privacy policy, in which User Content is defined as including the files and images you upload. The same document lists training AI models and choosing which adverts you see among the uses. You can opt out, through a link in the site’s header menu; it is on until you do. None of this is hidden. It is the ordinary price of a detector that has to receive your file before it can do anything at all.
Read it yourself: DeepAI’s privacy policy ↗
Where a classifier does better
A machine-learning detector looks at the pixels. We do not. On a picture stripped of everything, screenshotted, re-uploaded, re-saved. A good classifier can still see traces in the image itself that we have no way to read. We fall back to the shape of the file, which catches a great deal but not everything. If a check here comes back “can’t tell”, a pixel-based tool is a reasonable second opinion. We would rather say that than pretend the gap does not exist.