Fact-Check

How Exif Metadata Can Help You Authenticate Doubtful Images

November 24, 2021

How Exif Metadata Can Help You Authenticate Doubtful Images

Often, photographs are recycled and/or doctored to fuel interest and provide visual “proof” for fake news. Fake or manipulated images propagated through the web and social media have the capacity to deceive, cause emotional distress, and influence public opinions and actions. In other words, images lend emotion and legitimacy to stories, even when they’re not true.

Misappropriation or misrepresentation of images has helped to drive the growth of fake news and this is simply achieved by relying on images to sell bogus narratives.

The people publishing and promoting fake news routinely take photos out of context, digitally alter them. They also combine them with texts to manipulate readers, knowing that people tend to accept photographs as truthful representations.

This image was once used to portray the narrative that Nigeria’s President Muhammadu Buhari was dead and an imposter by the name Jubrin from Sudan had taken over the seat of power.

Knowing how to do a reverse image search can help you identify hoax images, but sometimes we need more details such as the date and time an image was shot, the make and model of camera and lens an image was shot with, as well as GPS coordinates if available; all of these can help to prove the authenticity of an image. These details are the image’s metadata.

Meta Data

Image metadata is text information pertaining to an image file that is embedded in the file or contained in a separate file that is associated with it. Image metadata can be very useful for cataloging and contextualizing visual information.

It includes camera details and settings such as aperture, shutter speed, ISO number, focal depth, dots per inch (DPI). Other automatically generated metadata include the camera brand and model, the date and time when the image was created and the GPS location where it was created.

Basic metadata information can be obtained by right clicking on the image from your device, scrolling down to properties and selecting, then clicking the ‘Details’ tab at the top of the popup window.

Metadata Analysis

The three main categories of image metadata are:

Technical metadata is mostly automatically generated by the camera. It includes camera details and settings such as aperture, shutter speed, ISO number, focal depth, dots per inch (DPI). Other automatically generated metadata include the camera brand and model, the date and time when the image was created and the GPS location where it was created.

Descriptive metadata is mostly added manually through imaging software by the photographer or someone managing the image. It includes the name of the image creator, keywords related to the image, captions, titles and comments, among many other possibilities. Effective descriptive metadata is what makes images more easily searchable.

Administrative metadata is mostly added manually. It includes usage and licensing rights, restrictions on reuse, contact information for the owner of the image.

Several standardized formats of metadata exist, including: Information Interchange Model (IPTC), Extensible Metadata Platform (XMP), Exchangeable Image File (Exif), Dublin Core Metadata Initiative (DCMI) and Picture Licensing Universal System (PLUS).

It’s important to note that metadata can easily be stripped out of a file (as is often the case with images that spread on social media), or even changed maliciously. So don’t rely on it 100%, and always try to cross-check your findings.

A good way to bypass this limitation is to search for other modified or original versions of the image using reverse image search, speak to the original source, double check landmarks with maps or satellite images among other techniques.

Exif Metadata

Exif metadata is a record which shows the digital SLR camera settings used to take a particular photograph. This data is recorded into the actual image file.

Therefore, each photograph has its own unique data. Exif data shows photo information such as camera model, exposure, aperture, ISO, what camera mode was used and whether or not a flash occurred.

The image below is an example of what exif metadata looks like. This information differs depending on what exif reader used to see the exif metadata.

How to Find an Image’s Metadata (Exif Data)

Jeffrey’s Exif Viewer Web App is a tool that helps in the verification of photos as it displays date, time and location data for the photo. It helps us to know if an image sent to a news desk or shared on social media is what it purports to be.

The simple tool allows you to upload a photo (or video or audio file) and see the exif data, detailing the time and date it was taken, the type of camera used and other details.

Geolocation details are recorded and displayed in the viewer and this can also be key when verifying images.

To use this tool, log on to the website

The interface looks like the above image with a range of options

Upload a file or add its public URL, then check the CAPTCHA, and hit “View Image Data.”

Once you scan a file, you should see a decent amount of information if it came from a smartphone. In my example below, the photos Exif data contained a GPS location.

The amount of information combined with other checks, such as when it was first uploaded, social timestamp, time, date, location, weather conditions, landmarks in maps to mention a few, can be very revealing for authenticating images.

The researcher produced this media article per the Dubawa 2021 Kwame KariKari Fellowship partnership with PRNigeria to facilitate the ethos of “truth” in journalism and enhance media literacy in the country.