A few days ago I wrote about the privacy implications of metadata in a PDF. This post will do the same for photos.
You can see the metadata in a photo using exiftool. By default cameras include time and location data. I ran this tool on a photo I took in Seattle a few years ago when I was doing some work for Amazon. The tool reported 114 fields, some of which are redundant. Here is some of the information contained in the metadata.
GPS Altitude : 72.5 m Above Sea Level GPS Date/Time : 2017:05:05 17:47:33.31Z GPS Position : 47 deg 36' 39.71" N, 122 deg 19' 59.40" W Lens ID : iPhone SE back camera 4.15mm f/2.2
How finely does this specify the location? The coordinates are given to 1/100 of a second, so 1/360000 of a degree. A degree of latitude is 111 km, so the implied accuracy is on the order of 30 cm or one foot, whether that’s correct or not.
You can look up that ground level at that location is 46 meters above sea level, which would imply the photo was taken on the 8th floor of a building. (It clearly wasn’t. Either the elevation of ground level or the elevation recorded in the phone isn’t correct.)
When I cropped the image, the edited image contained the software and operating system that was used to edit it.
Platform : Linux Software : GIMP 2.10.30 Modify Date : 2024:02:13 08:39:49
This shows that I edited the image this morning using GIMP installed on a Linux box.
You can change your phone’s settings to not include location data in photos. If you do, the photos may still include the time zone, which is a weak form of location data. You can remove some or all the metadata later using image editing software, but by default a photo reveals more than you may intend.
I vaguely recall that GPS is least accurate in altitude (in consumer receivers at least). That may have changed — it’s been a while since I last did any work with GPS.