A prime portrait is a prime number formatted as a matrix with X digits per line. When we select a color for each digit, we can generate an image.

Instead of doing this for many prime numbers and color schemes until you find something that resembles a known image, I have turned the process around. I have taken iconic images, such as the Mona Lisa and Starry Night, and converted them to images with only 10 colors. I assigned a digit to each color. Then I generated many similar images with a little bit of ‘noise’ added. The noise changed the colors in the images slightly, and thus the digits. If the digits in the image formed a prime number, I found a prime portrait!

source: L