What can a messaging attachment prove?¶

An attachment can show that a file or media item was associated with a message, conversation, account or device. Creation, deliberate viewing and personal responsibility are separate propositions requiring their own evidence.

Preserve the file-message relationship¶

A message record may hold the original file, a local path, attachment identifier, filename, size, thumbnail, download state and times. Preserve the best available file rather than only its on-screen preview, together with the surrounding conversation and account details.

Compare sender and recipient devices, exports, backups and other chats. Matching hashes can establish that two complete files are byte-for-byte identical; differing hashes do not necessarily mean unrelated content because a service may resize, compress or re-encode media.

Ask what happened before and after¶

The apparent sender may have created the file, downloaded it, received it elsewhere or forwarded it. Embedded metadata can assist but may be altered or removed during transmission. Earlier copies, editing artefacts, cloud storage and conversation context may better explain origin.

Receipt also does not prove that a person opened or understood the material. Applications can download attachments automatically or generate previews without deliberate action. State narrowly whether the evidence shows association, delivery, local storage, onward sharing or supported user interaction.