When you export a photograph, the image is the largest part of the file but not the only part. Understanding what else is in there is worth a few minutes before you hand one to a government portal.
What a camera file contains
- EXIF. Camera make and model, lens, exposure settings, the date and time, and on a phone usually GPS coordinates - which is to say, your home address if you photographed yourself at home.
- A thumbnail. A small copy of the image, embedded in the file. It is not always regenerated when the image is edited, which has historically led to thumbnails that still show the uncropped original.
- A colour profile. Describes how the numbers in the file map to actual colours.
- A DPI tag. The intended print density, discussed in millimetres, pixels and DPI.
- Software fields. Which application last wrote the file.
What to strip, and why
Location. There is no reason for a passport photo to carry the coordinates of where it was taken, and several reasons for it not to. Strip it.
Camera and software fields. Harmless but pointless, and they add weight to a file that may have a strict cap.
The embedded thumbnail. Worth removing both for size and because a stale thumbnail can show a version of the image you did not intend to send.
The date is a more interesting case. Since authorities enforce the recency rule by appearance rather than by metadata - which is editable and usually stripped on upload anyway - keeping it buys you nothing.
What to keep
The sRGB profile. This one matters. Portals and print labs assume sRGB, and a file tagged with a wide-gamut profile such as Display P3 can come out with shifted colours - which is a real problem when the background has to be a particular light grey.
Convert to sRGB rather than simply deleting the profile tag: deleting it leaves the numbers unchanged and the interpretation ambiguous, while converting makes the file say what it means.
The DPI tag, set to what the document expects. Some portals read it, most ignore it, and it costs nothing.
Why the weight matters
Metadata is small relative to an image, but not relative to a 240 KB cap. A full-size embedded thumbnail can be tens of kilobytes on its own. When a file is a few kilobytes over a limit, stripping metadata is a better fix than lowering JPEG quality another notch.
How not to strip it
Two popular methods that cause other problems. Screenshotting the photo removes metadata and also changes the pixel dimensions and re-compresses the image. Emailing it to yourself often strips metadata and resizes the attachment, so the file that arrives is not the file you sent.
Export properly instead, from a tool that produces the pixel size, colour profile and weight you asked for.
IDShot exports at the target pixel size with sRGB and the DPI tagged, and without location or camera metadata - the file contains the photograph and the two things a portal might actually read.