Look at what the file says about you

To read a photo's metadata before uploading, open its info panel: Photos on iPhone, Google Photos on Android, Preview on a Mac, Properties on Windows, or exiftool for everything. Watching a GPS coordinate and device model appear teaches more than any list. This is how to look; removing it is a separate step.

Built into the platform, no extra software

iPhone: Apple's iPhone User Guide says to tap the photo, "then swipe up or tap" the info button; a location line appears if one exists, with camera and date details further down.

Android: in Google Photos, swipe up on an open photo for a details panel; coverage varies by manufacturer, so treat it as reasonable but not exhaustive. Google's Photos Help page on locations adds a catch: "If a location was automatically added by your camera, you can't update or remove the location in Google Photos."

macOS: Preview's Tools → Show Inspector shows EXIF, IPTC and GPS panels for any open image, and Finder's Get Info shows a smaller summary. The command line goes further: mdls photo.jpg dumps the full Spotlight metadata index for the file, including fields the Preview panel does not surface.

Windows: right-click a file, Properties → Details, which lists camera, GPS and a long tail of other fields in one scrollable panel.

Web-based viewers exist for a quick check without installing anything, though uploading a file to a metadata-checking site to find out whether it has metadata is worth doing consciously rather than by habit, given the site now has the file.

Going further with exiftool

The built-in panels are a reasonable everyday check, but they do not all show everything a file contains. exiftool, a free command-line tool available on every major platform, lists every field it recognises - this is the tool that surfaces PNG text chunks and less common fields that a Finder or Explorer panel quietly omits. Running exiftool photo.jpg on a file straight off a phone is a genuinely useful five minutes: most people are surprised by how much is listed, not by any single field but by the total count. Installing it is a one-line command on every platform - a package manager on macOS or Linux, a downloadable executable on Windows - and it needs no account, no upload, and no network connection at all to read a local file, which is worth knowing given the slight irony of checking privacy tools online.

What to actually look for

Not every field matters equally. GPS coordinates and altitude are the ones with the sharpest consequence if a photo is ever shared beyond its intended audience. Device serial numbers and camera model matter less on their own but link files together across a set. Software and editing history fields are lower stakes but worth noting, since they can describe exactly what tool touched the file and when. Timestamps are usually low-consequence in isolation and higher-consequence in combination with anything else identifying. The filename itself is worth a glance too, since a name assigned by an app or a person can carry more information than it looks like it does.

Why this is worth doing before, not after

Checking after you upload tells you nothing about what the receiving service saw, only what remained if you look at a downloaded copy afterward - and by then the original has already made its trip. Check before, strip if warranted, and check again to confirm the strip worked, which is the same discipline the stripping guide recommends as its own final step. None of this changes how a scoring model reads the photo, since a model only ever sees pixels and never opens a metadata field, so there is no accuracy cost to being thorough here. It is worth doing for any photo going to a person as much as to a model - what belongs in a file sent to a human judge depends partly on what that file happens to be carrying. Services that treat data handling as worth disclosing in the open, rather than in a policy nobody reads, are also the ones worth favouring in a comparison - Penis Rater weighs this as a real differentiator rather than a footnote. The same habit applies before a photo goes anywhere useful for a measurement, too, even though the method itself does not depend on the file surviving intact.