2026-08-26
"Send as document" keeps your photo's full quality — and all of its metadata: what a 2025 forensic study measured
Every messaging app compresses photos by default, and the internet is full of guides for getting around it — for wedding photos, for a portfolio, for the close-up a buyer asked for. The advice in all of them is the same: don't send it as a photo, send it as a file. WhatsApp calls it a document, Telegram calls it a file, Signal has the same option, and the result is the same everywhere — the recipient gets your original, pixel for pixel. What almost none of those guides mention is that the compressed path you just stepped around was also, quietly, the metadata-stripping path. The document send doesn't just skip compression. It skips the only step that was removing your GPS coordinates.
The compressed send was doing privacy work you didn't know about
When you send a photo the normal way, the app re-encodes it — smaller dimensions, stronger JPEG compression, a fraction of the file size. Re-encoding builds a new file, and the embedded metadata of the old one mostly doesn't come along. In some apps that's a bandwidth side effect; in at least one it's deliberate policy. Signal's Android client has stripped EXIF from JPEG attachments since a change merged in March 2018, and the reason given in that change is telling: images that went through rescaling were already losing their metadata incidentally, but images small enough to skip rescaling kept theirs — including location — so the client now re-encodes every JPEG to make the stripping unconditional. Either way, the practical effect is the one most people never think about: the ugly, compressed version of your photo was also the version that didn't carry your coordinates.
A forensic journal measured exactly this in 2025
You don't have to take a blog's word for the difference — a study published June 18, 2025 in the journal Perspectives in Legal and Forensic Sciences ("Forensic Value of Exif Data," by Nishchal Soni) measured it, using controlled photo sets from Android and iOS phones and checking the results with ExifTool and commercial forensic suites. Sent as documents through WhatsApp, Telegram, or Signal, the received files "maintained identical hash values compared to the original captures" — MD5 and SHA-256 checksums matched the originals exactly, which means the recipient got the same bytes, every examined Exif field intact: timestamp, GPS geolocation, device make and model, editing software, embedded thumbnail. Sent through the same apps' ordinary photo mode, the files came out with different hashes and only 16.67% — one in six — of the examined Exif fields surviving. Instagram, Facebook Messenger, and Snapchat stripped to the same floor through their compression pipelines. USB cables and email attachments, for the record, behaved like document mode: byte-identical.
Read the framing, though. This is a forensics paper, and in forensics metadata surviving transit is the good outcome — an intact Exif block is evidence, and a matching hash is integrity. The paper's takeaway is that investigators need "platform-aware evidence handling." The exact property that makes document mode evidence-grade for an examiner is the property that should give everyone else pause: it is the transfer method that keeps everything.
Human-rights groups recommend document mode — because it keeps metadata
The clearest confirmation of what document mode does comes from people who want that behavior. Amnesty International's Citizen Evidence Lab — which trains people to document human-rights abuses — published a guide in April 2020 on sending photos so that the metadata survives, because for evidence, the GPS fix and the timestamp are the point. Its instruction: "To send full resolution images while preserving EXIF data, stop sharing images from your camera roll and share instead as a document attachment." Its summary of the default behavior: "Images sent as pictures from the gallery have most metadata stripped out," while document attachments preserve it. The same guide immediately adds a warning that cuts both ways: fully intact metadata can expose the photographer's identity and location, so it should only be shared with informed consent. Same button, opposite goals. An evidence workflow presses it to keep the metadata; a parent sending vacation photos presses it for the resolution and ships the metadata by accident.
And WhatsApp made that button mainstream
For years the document trick was messaging-app folklore. In December 2023 WhatsApp promoted it to an official feature: version 23.24.73 added original-quality photo and video sending, reached through the attachment menu's Document option — "Choose Photo or Video" — with a 2 GB cap. Coverage at the time (MacRumors, December 4, 2023) noted why the new path was needed at all: the existing HD toggle "still involved compression," while sending as a document "avoids compression altogether by allowing photos and video to be shared as files." Which is exactly right, and exactly the issue — a file shared as a file arrives as the file, GPS block and all. The quality-preserving path is now a first-class, discoverable UI, used by plenty of people who have never heard the word EXIF.
For PDFs and Office files, there is no stripping mode at all
One more consequence hides in the same mechanics. A photo at least has a compressed send that happens to launder metadata. A PDF, docx, or xlsx does not — a document sent through a messenger is sent as a document by definition, because there is nothing else it could be. The 2025 study's document-mode finding applies in full: byte-for-byte delivery, identical hashes. So the resume you WhatsApp to a recruiter, the contract you send to a counterparty, the spreadsheet you forward to a group chat — each arrives carrying whatever its docProps or Info dictionary carries: author name, company, last-modified-by, total editing time, producer software. This blog has covered what lives in those fields; the messaging-app angle is simply that no platform re-encode will ever save you, because for documents there isn't one.
Full quality without full metadata
The two goals — original pixels, no location data — are not actually in conflict. They only look that way because the messenger bundles them: its stripping lives inside its compressor. Unbundle them by stripping the metadata yourself, on your own device, before the file goes anywhere, and then use document mode freely. That is the case NearScrub is built for. Its JPEG path removes the EXIF/GPS block, XMP, IPTC, and comment segments by copying the file's segments selectively — the compressed image data is copied untouched, not re-encoded, so the whole reason you chose document mode (the pixels) survives unchanged. The one piece of EXIF it deliberately re-inserts is the orientation flag, a display-rotation number from 1 to 8, so portrait shots don't arrive sideways — the same problem Signal solves by re-encoding the pixels, solved instead by keeping the pixels and exactly one privacy-free tag. PNGs get their text, EXIF, and timestamp chunks dropped; PDFs get the Info dictionary cleared and the XMP stream deleted; docx, xlsx, and pptx get their core, app, and custom property parts blanked. All of it happens in the browser on your device — nothing is uploaded, which would be a strange thing to require of a tool whose entire point is controlling what leaves your phone.
Three honest caveats
First, HEIC. iPhones shoot HEIC by default, and a HEIC sent as a document travels byte-for-byte like everything else — but NearScrub does not currently parse HEIC, so it can't clean one; it will simply decline the file rather than pretend. Have the phone share a JPEG copy, or convert first, and scrub that. Second, hashes. A scrubbed file is a different file — different checksum — which is precisely what you want for privacy and precisely what you don't want if you're preserving evidence. If you're in the Citizen Evidence Lab's use case, documenting something where the timestamp and GPS fix are the value, don't scrub; that workflow needs the metadata and the consent question that comes with it. Third, versions. The 2025 study measured the apps as they shipped then, and app behavior changes; the compressed path's stripping is each platform's implementation detail, not a promise to you. The only step in the pipeline you control completely is what the file contains before you hand it over.
The habit
This blog once covered what marketplaces do to public listing photos — and noted that none of the tests covered photos sent by direct message. This is that other half, and it turns out to have a sharper edge: in a DM, the more you care about quality, the more likely you are to pick the one send mode that preserves everything. So the habit is short. If you're about to tap "send as document" or "send as file" — for the buyer, the group chat, the recruiter — ask what the file still contains, because whatever it contains is exactly what arrives. If the answer involves a photo straight off a phone or a document straight out of an editor, run it through a scrubber first. Full quality is a fine thing to send. It just shouldn't come bundled with everywhere you've been.