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Cover media

Visual media is part of how journalism is identified, shared and understood. PressChain therefore treats cover media as more than a decorative URL. The canonical Capsule metadata envelope includes both cover_media_uri and optional cover_media_hash. Canonical read models also expose a cover_url, and the V3 evidence record includes coverUrl and metadataURI fields for evidence presentation.

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Store a durable reference

A cover URI should resolve to the media artifact or to a durable content address. Avoid using a temporary image optimization URL that contains a short-lived signature as the canonical reference. Your delivery stack can still create transformed thumbnails. Keep the original canonical reference and hash available for verification.

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Hash the original bytes

If cover_media_hash is present, hash the exact canonical media bytes before upload or immediately after retrieving the stored object.
Use the hash algorithm required by the canonical metadata implementation for the specific field. The snippet above demonstrates browser byte hashing and should not replace a protocol-defined algorithm when one is specified.

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Rich Capsule cards

A good Capsule card can show:
  • cover image
  • title
  • author and outlet
  • publication timestamp
  • canonical source
  • content and metadata verification state
  • evidence count
  • revision count
The cover should not be cropped so aggressively that important journalistic context disappears. Preserve aspect ratio metadata in the application layer when available.

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Evidence media

Evidence has its own coverUrl. This is useful for a PDF preview, photograph, scan, chart or other visual artifact associated with the evidence item. Keep the distinction between the evidence uri, which points at the evidence artifact, and coverUrl, which is a presentation reference. A screenshot preview is not a substitute for the underlying source document.

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Handling unavailable media

A missing image should not make the Capsule unreadable. Fall back to title, identity and verification data while preserving the original URI and hash in an inspection view. Useful states include:
  • media verified
  • media available but unverified
  • media hash mismatch
  • media unavailable
  • no cover declared
This is more accurate than silently swapping in an unrelated stock image.

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Why first-class media matters

Explorer and Portal surfaces can use the same canonical cover reference to render recognizable records. Third-party applications can do the same without scraping an article page for Open Graph metadata. That produces a better developer contract: the publication record itself says which media belongs to it and, when a hash is provided, how to verify that media.