Do you know what CSS is? If not, it stands for Cascading Style Sheets and the code it uses gives website the styles (fonts, colors, backgrounds, etc.) that are visible to the user. I know CSS enough to understand it and work with it a little bit.
Javier Román Cortés created Homer Simpson with it and is definitely an extremely advanced CSS user though. This is really incredible and just blows my mind. In order to see what this guy had to do to create this image, you can highlight the photo with your mouse, right click, and choose “view selection source.” That’s a whole lot of code.