An Australian cyber researcher alleges that social media giant Facebook embeds tracking codes in monitor who sees and shares your photos.

Forbes reports that Australian cyber researcher Edin Jusupovic recently claimed on Twitter that Facebook is embedding “hidden codes” in photos that users upload to the site to track how many people see and share the photos.

“Facebook is embedding tracking data inside photos you download,” Jusupovic stated on Twitter adding that he had “noticed a structural abnormality when looking at a hex dump of an image file from an unknown origin only to discover it contained what I now understand is an IPTC special instruction.”

#facebook is embedding tracking data inside photos you download. I noticed a structural abnormality when looking at a hex dump of an image file from an unknown origin only to discover it contained what I now understand is an IPTC special instruction. Shocking level of tracking.. pic.twitter.com/WC1u7Zh5gN — Edin Jusupovic (@oasace) July 11, 2019

Jusupovic stated that this was a “shocking level of tracking,” adding that “the take from this is that they can potentially track photos outside of their own platform with a disturbing level of precision about who originally uploaded the photo (and much more).”

The “IPTC special instructions” that Jusupovic describes are essentially digital watermarks embedded in image metadata by Facebook, which the company can then access again at a later date. These methods have been used for some time and have many applications such as tracking the ownership of images, resolving copyright infringements, enhancing user services, and improving targeted advertising.

One analyst noted that these tags have been added to images since 2016 and “contains an IPTC block with an ‘Original Transmission Reference’ field that contains some kind of text-encoded sequence. This coding method lets Facebook ‘know it has seen the image before when it gets uploaded again.'” One user on Reddit explained it simply stating: “It is yet another way to learn associations between people. Person 1 uploaded a bunch of the same photos Person 2 uploaded, let’s show them both all the same advertisements!”

Members of Congress have been focusing more closely on the actions of social media sites for some time now, Senators Richard Blumenthal (D-CT) and Josh Hawley (R-MO) wrote to the FTC in May urging the commission to probe Facebook “to compel sweeping changes to end the Facebook’s pattern of misuse and abuse of personal data.”

Social media hearings before Congress are taking place tomorrow, “Online Platforms and Market Power, Part 2: Innovation and Entrepreneurship,” will take place tomorrow on July 16 at 2:00 p.m. EST while another hearing titled “Google and Censorship through Search Engines,” will take place tomorrow at 2:30 p.m. EST.

Lucas Nolan is a reporter for Breitbart News covering issues of free speech and online censorship. Follow him on Twitter @LucasNolan or email him at lnolan@breitbart.com