They capture different things
A screenshot records a visible view at a moment. It can show interface details and a particular passage, but what falls outside the frame is absent. Several screenshots can overlap, skip messages or obscure the sequence when rearranged.
A native export provides text and, where supplied, media that can be searched and presented as a conversation. It does not preserve every visual detail of the original app screen, and it is not guaranteed to contain the full history.
Neither form independently proves who wrote a message, whether the material was altered before you received it, or whether it will be accepted in a formal process.
Compare the same passage
If you have both, keep them separately and compare the relevant dates, participant labels and surrounding messages. Record discrepancies instead of changing one source to match the other. A difference may need explanation; a preparation tool cannot settle it.
Fictional example: a screenshot shows “Friday works.” The native export also includes a later message saying “Please wait for confirmation.” A reviewer needs the later context to understand the exchange. The example illustrates selection, not a rule about the legal effect of those words.
Preserve before annotating
Keep original screenshots and native exports independently. If you crop, highlight or annotate a working copy, distinguish that copy from the original. Avoid recreating a conversation by typing screenshot text into a file and calling it a native export.
UnPack accepts supported native TXT/ZIP exports, not screenshots as native chat imports. It does not recover the messages outside an image or reconstruct missing attachments.
Choose for the review purpose
A searchable export can make a long conversation easier to navigate. A screenshot may help explain a visual detail that the text export does not show. Retain useful supporting material rather than assuming one format replaces every other source.
For a legal process, ask the reviewer what source and supporting information they need. Formatting and conversion do not decide authenticity, admissibility or evidential weight. This is preparation guidance, not legal advice.