Here's a second demo for the hell of it
Images are just grids of pixels. When you resize or rotate them, you basically have to insert new pixels/data (i.e. interpolate) based on what sort of end result you want. Nearest neighbor is the fastest because all it does is make the new pixel the same color as the closest original.
In broader terms, though, I guess you could say this is the same as anti aliasing (Not that I'm directing this at anyone)
Long story short, most people have better computers now than they did 10 years ago and it'd be nice to see some of this