Does editing the metadata re-compress the photo?

No, and that is the point. A JPEG is a header followed by entropy-coded image data, and the metadata lives entirely in the header. This tool rebuilds one segment — APP1 — and copies every other byte through unchanged, so the compressed picture in the output is bit-for-bit identical to the input. Tools that decode and re-encode cost you a generation of quality every time you correct a date.

Why did my file get slightly bigger or smaller?

Because the new EXIF block is a different length from the old one. The change is tens or hundreds of bytes and is entirely header; the image data has not moved a bit. The status line reports the exact delta so you can see that for yourself.

What happens to metadata this editor does not cover?

The whole EXIF block is replaced by the one built from these fields, so any EXIF tag not listed here is dropped. That is why Read existing metadata exists — press it first and the fields are prefilled from the file, so a single edit does not quietly discard the other twenty. XMP, IPTC and the ICC colour profile live in different segments and are left completely alone.

Will the GPS coordinates show up in Photos or Google Maps?

Yes. Latitude and longitude are written as the three-rational degrees/minutes/seconds form the EXIF specification requires, with the correct N/S and E/W reference tags, which is what every consumer photo app reads. Decimal degrees go in the boxes — the conversion happens here.

Can I clear the metadata instead?

Empty every field and run it: with nothing to write, the APP1 EXIF segment is removed rather than replaced. For a thorough strip that also takes XMP, IPTC and comment segments, use Remove EXIF instead.

Edit EXIF Metadata in a JPG

lossless — the image is never re-encoded · date, camera, lens, GPS · batch · in-browser

Fix a wrong date, credit a photographer, add a copyright line, or write GPS coordinates onto a scan — without touching the picture. A JPEG keeps its metadata in a header segment separate from the compressed image, so the honest way to change it is to rebuild that segment and copy the rest through byte for byte. That is what this does: the pixels in the output are bit-for-bit identical to the input, every time. Nothing is uploaded.

Drop JPG files here

JPG / JPEG only · multiple allowed · the same fields are written to all of them

Prefills the fields from the first file, so one edit does not wipe the rest. Delete the metadata instead of writing it

Camera & description

Camera make Camera model Lens model Software

Description Artist Copyright User comment

Dates

Date taken Date digitised File date

Exposure

ISO F-number Exposure time, seconds Focal length, mm Orientation

Location (decimal degrees — both are needed, or neither)

Latitude Longitude Altitude, m

no files

Ready.

How to use it

Drop the JPGs. If you are correcting one photo, press Read existing metadata first — the fields fill in from the file and you edit from there.
Fill in what you want written. Leave a field empty and that tag is simply not written.
Dates use the EXIF format YYYY:MM:DD HH:MM:SS — colons in the date part, which looks wrong and is correct.
Press Write metadata. Every queued file gets the same fields, and each result reports whether an existing block was replaced or a new one inserted, plus the byte delta.

Where metadata actually lives in a JPEG

A JPEG is a sequence of marker segments. APP0 is usually JFIF, APP1 holds either EXIF or XMP, APP2 commonly carries the ICC colour profile, DQT holds the quantisation tables, and after SOS comes the entropy-coded image data that is the actual photograph. Metadata is entirely in the APPn segments before it.

So a metadata edit does not need a decoder at all. This tool walks the markers, builds a fresh APP1 EXIF segment from your fields, and writes out: everything before the old segment, the new segment, everything after. If the file had no EXIF, the new segment is inserted straight after APP0, which is where readers expect it.

The EXIF block is a small TIFF file

Inside APP1, after the six bytes Exif\0\0, sits a complete TIFF structure: a byte-order mark, a magic number, and a pointer to the first image file directory. Each directory is a list of twelve-byte entries — tag, type, count, and then either the value itself or a pointer to it. Four bytes or fewer go inside the entry; anything longer is written to a data area and the entry holds the offset.

Two rules from the specification are where hand-written EXIF usually goes wrong, and both are followed here: entries in a directory must be sorted by ascending tag number, and every value offset must be even. Get either wrong and you produce a file that one reader accepts and the next one rejects. Camera settings live in a sub-directory reached through tag 0x8769, and GPS in another through 0x8825 — which is why those pointers have to be counted before any offset can be worked out.

EXIF viewer — read everything a photo carries, including tags this editor does not write.
Remove EXIF — strip EXIF, XMP, IPTC and comments in one pass, losslessly.
Change DPI — the same lossless header-rewrite trick, applied to resolution.

Edit EXIF Metadata in a JPG

How to use it

Where metadata actually lives in a JPEG

The EXIF block is a small TIFF file

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