Hidden Imagery In AI Art refers to a series of optical illusion images generated using AI art tools, primarily Stable Diffusion, which spell out words or contain the outlines of various imagery in AI art. Often, a viewer must step backward or see a smaller version of the image in order to read the word or see the outlined imagery concealed within it. Around mid-July 2023, such images began appearing online alongside the rise of artificial intelligence content, becoming increasingly prevalent online throughout the year as sites like Glif emerged.
On July 17th, 2023, Redditor /u/Ordinary_Ad_404 posted a tutorial for "images with 'hidden' text using Stable Diffusion and ControlNet" on the subreddit /r/stablediffusion, which received nearly a thousand upvotes over the course of two months. For example, they used a series of images (seen below) with the text "New York" embedded inside them.
The AI technology enabling this kind of content came about on June 26th, 2023, when Monster Labs released a package on Hugging Face (a platform where AI researchers and enthusiasts post code and models they're working on) that allowed users to generate QR codes hidden inside of other illustrations.
The package worked via ControlNet, a new function added onto the AI art generator Stable Diffusion. ControlNet, which was introduced in a February 2023 paper called "Adding Conditional Control To Text-to-Image Diffusion Models" by Lvmin Zhang, Anyi Rao, and Maneesh Agrawala, allowed users to give the Stable Diffusion art AI two different prompts at the same time (example video shown below).
The first prompt, for example, could be the QR code and the second prompt could be whatever image the QR code was supposed to be hidden in. Then, Stable Diffusion (using ControlNet) would produce the two images at the same time. This same technology was behind memes like Spiral Town, which also featured one image superimposed within another.
On September 18th, 2023, Redditor /u/3deal posted a "subliminal advertisement" AI-generated image of people walking on a rainy street with the letters of the word "OBEY" spelled out by their dark clothing (seen below). The post received almost 2,000 upvotes on the /r/stablediffusion subreddit in roughly 48 hours. On the subreddit, some users suggested that the images be called "pareidolia" images, after a medical word meaning "the tendency to perceive a specific, often meaningful image in a random or ambiguous visual pattern."
Later that day, the same image was then reposted to X (seen below) by @DiffusionPics, an account central to many artificial intelligence trends, receiving over 6,400 likes and 1,300 retweets over the course of 48 hours.
Others posted similar images in the following days. For example, on September 19th, 2023, X user @fabiansteltzer posted a series of images generated using ControlNet that placed words on top of a picture, like one (seen below, left) with the text "OKAY," which received over 1,000 likes over the course of a day. Earlier, on September 17th, user @JakeArkinstall posted another image within the trend (seen below, right) on X, earning just over 40 likes in three days.
Many connected it to another series of AI generations related to Spiral Town memes, which used ControlNet to render a series of images that showed one thing superimposed on top of another.