Steganography examples are especially fun when they are images. Since "everything’s a number”, we know that images are really made up of a series of red, green, and blue numeric values. It turns out that if we change the values of these numbers slightly, our eyes really can’t tell the difference in the colors. If a color has a red value of 237, for example, it may look no different from a color with red value anywhere between 230-239. The last digit does not change the hue enough to notice. Since part of the numbers don’t really matter in terms of how the overall picture looks, those numbers become a great place to hide information. That last digit is like one of the circled letters in the secret book. If you look at enough of these secret hiding spots and put the information together, a new message is revealed.
Note, the code in this example sets the hide image to the result of dividing every pixel by 16 so all the colors' component values are all low numbers (i.e., 16 or less), making the entire image look basically black.
Drop your images onto the area above to make it available within your code editor on this page. Note: your images will not be uploaded anywhere, they will stay on your computer.