JAYPEGERY WASH · DRY · FOLD · CONVERT

THE LINT TRAP

Reading locally: nothing is uploaded

See what a photo is carrying (the camera, the timestamp, the coordinates), then take it out without touching the picture.

LINT TRAP — INSPECTION EMPTY

What is in there

Every photograph your phone takes carries a block of structured data alongside the picture. The camera model and its firmware. The aperture, shutter speed and ISO. The moment the shutter fired, often to the second and with the time zone you were standing in. And, if location services were on for the camera, the latitude and longitude, routinely to six decimal places, which is a precision of about a metre.

None of it is visible when you look at the picture, and all of it travels with the file. Most large social platforms strip it on upload; almost nothing else does. An emailed attachment, a marketplace listing, a forum post, a file sent through a chat app as a document rather than a photo, all of those preserve it exactly.

A photo taken in your living room and posted to a forum contains your home address to within a few metres, and reading it back requires no expertise at all.

Taking it out without touching the picture

The usual advice, which this site used to give, is to convert the file, because re-encoding through a canvas builds a new file from pixels and leaves the metadata behind. That works, but it costs you a generation of lossy compression for a job that should cost nothing.

Empty the trap does it properly. A JPEG is a sequence of segments: a header, some tables, the metadata blocks, and then the compressed image data. Removing metadata only means writing the file out again without those particular segments and copying the compressed data across verbatim. The picture that comes back is byte-for-byte the picture that went in. Nothing is re-encoded, so nothing is lost.

Colour profiles are kept on purpose. An ICC profile lives in its own segment and describes the picture rather than you; dropping one shifts every colour in the image, which is a real cost for no privacy gain.

Questions at the counter

Is my photo uploaded to check it?

No, and that matters more here than anywhere else on this site. Checking whether a photo discloses your home address by first sending that photo to a stranger’s server defeats the purpose. This page reads the file on your own machine. Open your browser’s developer tools and watch the network tab, or turn off your wifi after the page loads and inspect a photo anyway. It still works.

How is “empty the trap” different from just converting the file?

Converting re-encodes the picture: the image is decoded to pixels and compressed again, which costs a generation of quality on any lossy format. Emptying the trap rewrites only the file’s container. It drops the metadata segments and copies the compressed image data across untouched. The picture is byte-for-byte identical to the original, so it is genuinely lossless.

Why only JPEG?

Because that is where the problem is. Exif is a JPEG and TIFF convention, and it is what cameras and phones write. PNG, WebP and GIF can technically carry metadata blocks, but cameras do not put GPS coordinates there, so a reader for them would be a reader for an empty room.

It says no metadata was found. Is that good?

Usually, yes. It means either the camera never wrote any, or something already removed it: most large social platforms strip metadata when you upload, and any previous format conversion will have done the same. A file with nothing in it has nothing to leak.

Does the colour profile survive?

Yes, deliberately. ICC colour profiles are held in their own segment and are kept, because dropping one shifts every colour in the image. Only the Exif, XMP, IPTC and comment segments are removed, the things that describe you rather than the picture.

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Need the format changed as well? Every route on the board strips metadata too, as a side effect of re-encoding. Use those when you want a different format, and the trap when you want the same file minus its record.