Practical Privacy Guide: How to Remove EXIF Metadata from Photos on Mac OS

Perhaps you were at a protest and took photos of the action, and plan to upload them to social media. Or an ex who has not 'moved on' has been able to easily search publicly available databases to find out where you live and work, and is now scouring your online posts using a dummy account posing as a professional in your field.

What if that ex could determine: your exact GPS coordinates where you take photos, what type of phone and camera you used, its serial number, and the exact date and time you were snapping selfies with you and your new partner at your regular hangout? Maybe you are simply trying to limit the amount of private data that you are potentially sharing each time you attach one of your photos to an email. Whatever your particular OpSec (operational security) needs are, it is crucial that you understand what you can do to limit or eliminate the most sensitive data that your photos reveal.

Before you share photos publicly, consider the buffet of personally sensitive EXIF (Exchangeable Image File Format) metadata visible each time you capture an image, and the privacy implications for your unique situation. 

EXIF metadata is like a digital passport that is embedded in your photos. It tracks a good deal about how and where an image was captured. This guide provides practical advice on how to easily strip EXIF metadata from your images on MacOS (regardless of where the photos originated) before they are uploaded or shared.

The EXIF metadata in your photos includes (short list): 

    • Make and model of smartphone or camera

    • Unique device identifiers

    • Date and time the photo was taken

    • Original date when the image was created

    • Digitized timestamp

    • Timezone information

    • Location and GPS data, including the latitude and longitude coordinates

    • Can pinpoint your exact location at time of capture

    • Depending on device type, unique identifier tags and extensive location data, and device serial numbers 

This a truncated list of the abundant data that can be gleaned from photos you take and share online.

This metadata can be used to identify you and your location across accounts, platforms, and sessions. Combined with some sleuthing, public databases, property records, and some creativity, an adversary can determine a wealth of information that can reveal what you do, where you do it, with what device, the locations where you work and play, your phone numbers, email addresses, your employer, and, disturbingly, who your family members and associates are. 

This is why it is critical to strip the metadata from your photos.

There are multiple tools to remove it. For the average user who wants to do this quickly and easily on Mac using a GUI (graphical user interface), your best bet is the ImageOptim application. 

ImageOptim application is free, open source, and works via a simple drag-and-drop interface. ImageOptim also works via CLI (command-line-interface), but the GUI fits seamlessly in a desktop workflow. It is available as a direct download, via HomeBrew download, or on the Mac App Store. (But who uses that, right?)                                                  

ImageOptim not only strips the metadata, it also compresses the image and reduces its file size, often by over half, without visibly affecting the quality of the photo. This can be majorly convenient when you are bulk uploading, or working within file size constraints. If you're a prefessional photographer uploading high-res images to your website? Not so much.

Once you have downloaded and installed ImageOptim, open it from your Applications folder. Once launched, you'll see this main screen:

Next, navigate to the top left of screen and select ImageOptim > Settings, and you'll see this window to customize your settings:

Ensure that you have selected the two boxes "Strip PNG metadata" and "Strip JPEG Mmetadata." Note the "not recommended if you rely on embedded copyright information" message, if you want to retain embedded copyright.

The other two settings, Quality and Optimazation speed, allow you to customize how fast the image is processed vs the image quality. Enabling lossy minification in the Quality settings creates a much smaller image size (fine for everyday photo postings).

Once you have customized your settings (ensure that you selected the 'Strip JPEG/PNG metadata') you are ready to begin removing sensitive private data from your photos.

Navigate in Finder to the folder where the images you want to process are, and select them with your cursor, then drag and drop them into the ImageOptim window or App icon in your dock. You can also use the + icon at the bottom left of the ImageOptim screen to select file/s. I used a test image with the filename 'Remove my GPS Location' You should see something like this:

ImageOptim has stripped the metadata, and per my customized preferences, reduced the file size, on this image, it resulted in a 76.4% savings. Now the original photo has been modified to remove private data, and is saved in its original location--ready for upload. (If you want to retain your original image pre-strip, make a copy of it before running it in ImageOptim and clearly label it so you don't accidentally upload the original with GPS details.)

Your image is ready to share or post, and no longer contains privacy-compromising EXIF metadata. Once you've processed a few images, you can perform this with multiple photos at once. When I'm processing 30 photos or less, depending on file size, it generally only takes a few seconds to complete.

While there are multiple options (exifcleaner, exiftool) for photo metadata removal, ImageOptim excels at GUI ease-of-use, dual-purpose action (metadata removal and file size reduction) and seamless integration to a desktop workflow.

This practical privacy guide was written completely without the use of artificial intelligence tools. Author retains copyright and not part of this may be reproduced without explicit written permission from the author.