"Is this image real?" used to be a question for photo editors. Now it's a question for every platform that accepts uploads, from marketplaces and dating apps to newsrooms and KYC flows.

In this post we'll look at how AI image detection works in practice: the pixel and frequency artifacts that classifiers learn, the provenance metadata standards like C2PA, and invisible watermarks like Google's SynthID. We'll also run two small experiments you can try on your own machine.

Three ways to answer "was this made by AI?"

Approach What it looks at Strength Weakness

Artifact detection The pixels themselves Works on any image Probabilistic; can be fooled by resizing, compression and new models

Provenance metadata (C2PA) Signed "Content Credentials" attached to the file Strong, cryptographically signed evidence when present Easily lost by screenshots and re-encoding

Watermarks (e.g.…