How To Detect AI Images For Legal Evidence

When an image may be used as evidence, in a lawsuit, an insurance claim, an employment dispute or a police report, the question "is it AI?" has to be answered in a way that holds up. A detector score from a website won't. This is general information, not legal advice; talk to a lawyer about your situation.

Preserve the original

• Get the original file, not a screenshot or a copy sent through a messaging app, which strips data.
• Don't edit or re-save it. Work on copies.
• Record a hash: a SHA-256 fingerprint of the file (from certutil -hashfile file SHA256 on Windows or shasum -a 256 file on Mac) shows later that it hasn't changed.
• Document where it came from, who handled it and when: the chain of custody.

Document what the file says

Record the metadata and any Content Credentials. Content Credentials Verify shows signed histories. In Chrome, AI Image Detector (made by Patrick Bushe, who runs this site) lists EXIF, IPTC, XMP and PNG fields, including AI tool names and camera details, without uploading the file. ExifTool produces a full, exportable report. Screenshot or export each result with the date.

Why detectors aren't proof

• Visual detectors give probabilities and have known error rates, including false positives on real photos.
• Results can change as models are updated.
• Metadata can be stripped, added or edited.

In the US, evidence must be authenticated (Federal Rule of Evidence 901 in federal courts), and the other side can challenge it. A score with no explanation is easy to attack.

Use a qualified expert

For anything contested, a digital forensics expert can examine the file's structure, compression history, device signatures and context, and testify about methods. Choose one with relevant experience and be prepared for the other side to have one too.

Context evidence

Other evidence often matters more: witnesses, other photos or video from the same time, device records and account data showing when the image was created and sent.

See verifying an image's source.