A C2PA metadata checker reads the label. It cannot validate the signature chain from the file alone.

The Coalition for Content Provenance and Authenticity defines a format for attaching provenance claims to media. A manifest holds assertions: who created the asset, with which tool, and which edits were applied, each recorded as an ingredient.

Those assertions are signed, so a verifier can check that the manifest was not altered after signing, and can see which certificate signed it.

Content Credentials is the consumer-facing name for the same idea, popularised by Adobe. It is one implementation of C2PA, not a separate standard.

A file-level checker scans the bytes for the manifest container and for the strings that identify provenance systems and generators. That produces an inventory rather than a verdict.

Reading a marker is not validating a signature. Full validation requires parsing the manifest, checking the signature against a trust list, and confirming the hash of the asset matches the claim.

A browser-side check can do the first step and reason about the presence of the rest. It cannot fetch a trust list and present a chain of custody as established, and it should not imply that it did.

This is the honest limit worth knowing when a client asks whether an image is verified: markers present is a statement about the file, not about the world.

Resizing, format conversion, screenshotting and most social platforms strip or drop embedded metadata. The asset that reaches your CMS is frequently not the asset that was signed.

The practical consequence is that absence is the normal state. A file with no manifest is evidence of a lossy path, not evidence of tampering.

If provenance matters to a workflow, capture it at the point of export and store it alongside the delivery: the manifest, the file hash, the date and the tool. That record survives the pipeline even when the pixels do not.

When a manifest is present, keep the file rather than the screenshot, and note which tool signed it. That is the beginning of an evidence trail.

When it is absent and the image is used as evidence, ask the supplier for the original file and the export path. Most suppliers can produce the camera original or the generator's signed output.

When it is absent and the image is decorative, do nothing except stop claiming provenance you do not have.

Platforms are progressively adopting disclosure labels and manifest preservation, and camera manufacturers are shipping signing at capture. The direction of travel is signed media as a default rather than an extra step.

Until then, treat provenance as a property of a workflow rather than of a file. The organisation that signs at creation, records the hash at export and stores both has an answer; the one that checks a screenshot does not.

A cheap check at every hop is more useful than an expensive audit after publication.