Hidden in Plain Sight: The Steganographic Image
Professor Jussi Parikka is a Finnish media theorist who works at the Winchester School of Art, University of Southampton.Read full Bio
Who knows what went into an image, what it includes and what it hides? This is not merely a question of the fine art historical importance of materials, nor even a media historical intrigue of chemistry, but one of steganography – hiding another meaningful pattern, perhaps a message, in data; inside text or an image. This image that is always more than. More than what? Isn’t it obvious from the amount of work gone into art-theoretical considerations of the inexhaustible meanings of the photographic image that it has always been a multiplicity: contexts, fluctuating meanings, readings and the insatiable desire to look at things in order to discover its depths.
As such, a steganographic inscription is neither a depth nor the plain surface but somewhere in between. In contemporary images made of data it refers to how the image can be coded as more than is seen, but also more than the image should do. The steganographic digital image can be executed; it includes instructions for the computer to perform. Photographs as part of a longer history of communication media are one particular way of saying more than meets the eye, but this image also connects to histories of secret communication from the early modern period, to more recent discussions in security culture, as well as fiction such as William Gibson’s novel Pattern Recognition (2003). Were J.G. Ballard’s 1950s billboard mysteries one sort of cryptographic puzzle that hid a message in plain visual sight?
The steganographic realities of writing and creating images as patterns within patterns have for a longer period considered the possibilities that any inscription can nest whole alternative worlds of inscriptions. It also goes way further back in time than examples from the 20th century, let alone digital culture. Perhaps not so much in terms of images but in devising systems for of secret messaging, Athanius Kircher (1602-1680) contributed to steganography as one particular version of communication that exceeds what is in front of your eyes in plain sight. The work Polygraphia nova (1663) provides elements for a carefully crafted codification apparatus that itself is telling of the culture of “secret monastic languages and codes of mediaeval Europe.” 
As later iterations of what Kircher and even before him the Abbot of Sponheim, Johann Trithemius von Trittenheim (1462–1516) started, the current digital image culture worries about particular techniques of the stegosploit – a mixture of steganography and exploit. But why worry, why is the first reaction one of concern? Because this is sort of an image is more likely to be analysed to its constituent pixels and “least significant bits” by computer security experts and hackers than art theorists or historians. This image operates in a reality that is more likely to be about the contagious image, the trickstery of operational code, the vulnerabilities in infrastructures that sustain the visibility of digital images.
The principle sounds relatively straightforward. JPEG and PNG images can include malicious bits of code that work inside the pixels. The pixel space that codifies what we perceive as an image catered to our human eyes, also includes the writing of more dynamic potentialities of execution. The executable bit in pixels can then be “decoded using an HTML 5 Canvas element that allows for dynamic, scriptable rendering of images.” An image format like PNG or Portable Network Graphics can acquire an additional meaning to its portability: for example, by installing spyware, it can piggy back the true triggering of a computer process.
Although, it is clear that in most cases we don’t suspect images: we scan through them, click, download, pass on, look at and forget without much effort. Sometimes we don’t even realise when we are looking at a file that is actually an image. The visual aspect of an image (file) is sometimes merely an interface to further events, triggering a cascade of computer processes.
Media scholar Tony Sampson has convincingly mapped the modern interest in contagious images. In his narrative, it reaches back to the late 19th and early 20th century theorists of the crowd, and the involuntary subjects that are mesmerised by the powers of contagious images and affects. In the book Virality Sampson quotes Gustave Le Bon on mass persuasion, attributing a “great power to the image as [hypnotic] organiser of the crowd”. While Le Bon might have been interested in mental images, the digital stegosploited image culture is a continuation of this particular trait of the contagious image, that works both across human users and their computational infrastructures. It’s not merely the computers that turn into zombies but the (barely?) half-conscious users that are zombielike in this particular collaboration. Your eyes lead into the infrastructures of computationality: not for you to see, but merely as one particular part of the chain of triggers.
One could justifiably say that the steganographic image is part of what Trevor Paglen calls operational images, a term he picks up from Haron Farocki. Quoting Paglen: “Instead of simply representing things in the world, the machines and their images were starting to ‘do’ things in the world. In fields from marketing to warfare, human eyes were becoming anachronistic.”
Such an image connects to techniques of surveillance and domination, but in our case also to the long history of trickster and false perceptions: not merely of thinking you saw something else you did, but that the image implicated you in a process beyond your intentions. Paglen continues: “Nowadays operational images are overwhelmingly invisible, even as they’re ubiquitous and sculpting physical reality in ever more dramatic ways. We’ve long known that images can kill. What’s new is that nowadays, they have their fingers on the trigger.”
The stegosploited image does not necessarily kill, but it does execute, and participates within the longer history of image as one of psy-ops: the image itself conducive to contagion.
 Fletcher, J. E. (2001) A Study of the Life and Works of Athanasius Kircher, ‘Germanus Incredibilis’. London:Brill, p.167