If you're old enough you may have seen the times when programmers wrote code as optimal as possible given the computers available back then. I remember 3D shooter games that would average 300 - 400 KB in size and you would play countless levels for days. Here's for example a 96 KB 3D shooter game called .kkriger that will leave you breathless.
If you try now to explain people these days that it takes less space to write a 3 minutes HD animated video and music clip than than it takes to store a 32×32 pixel icon they won't believe you. Not now when a plain jpeg image used on some website is > 50KB. So here's a guy called Iñigo Quílez who demonstrates just that using the image analogy. He writes a x86 real mode demo using Photoshop. The entire program is done by creating a 9x9 pixels image, filling each pixels with carefully chosen colors to represent the correct opcodes (who needs compilers, right ?) The image is then saved in a .raw format (no headers) then renames it to a .com file so that Windows recognize it as a executable. The animation is a infinite moving tunnel with a gray colored texture created with an XOR pattern, blurred, and deformed using a plane deformation technique to produce the animation.
This is the "source code" resized 10 times in a png extension
And here's the guy in action proving his mad skills.