Do your photos reveal your location?

A photo is more than a picture. Alongside the image, most cameras and phones save a block of information called EXIF: the device model, the settings, the time and, often, the GPS position to within a few metres.

Nothing shows this when you look at the photo, which is why it's easy to forget. Share the original file and all of it goes along.

What can be in the file (link to section)

• Location: latitude, longitude, altitude and sometimes the direction you were facing.
• Time: the exact moment, often with a time zone.
• Device: make and model, and on some cameras a serial number.
• Name: some cameras and editing apps add the owner's name or a copyright line.
• Software: the app that last saved the file.

One photo says where you were at a particular moment. Several taken at home at night can reveal your address, even if the pictures show nothing but a cat.

When it travels, and when it doesn't (link to section)

It depends on how the file is sent, not on what's in it.

Usually stripped from what others can see: large social networks and some messaging apps, which recompress images on upload. They may keep the data themselves.

Usually kept: email attachments, cloud storage links, and chat apps when you send a photo "as a file" or "as a document". Forums, marketplaces and smaller sites vary, so don't assume.

Check one of your own photos (link to section)

The surest way to know is to look. Your file is read in your browser, and nothing is uploaded.

Three ways to protect yourself (link to section)

1. Remove it before sharing. This strips the data without touching the image, so there's no loss in quality.
2. Turn it off at the source. On iPhone: Settings → Privacy & Security → Location Services → Camera. On Android, look in your camera app's settings. Menu names vary by version and maker.
3. Look at the picture too. Metadata isn't the only thing that gives you away. House numbers, number plates, street signs and reflections are all in the pixels, and removing metadata won't touch them. Redact or blur those.

For step-by-step instructions, read how to remove EXIF data from photos.