It's so laughable that people now all claim programming has always been easy.

I give you a bunch of high school students with average grades and no programming experiences. How long do you need to educate them so they can implement a JPEG decoder from JPEG spec, without a reference library?

It's a 100% unambiguous task. One doesn't need to understand the math behind discrete Fourier transform to implement JPEG. It's just a 1 to 1 translation from the spec to code. Must be not so hard!