I think it's just interesting to a lot of the HN audience. A modal HN reader stumbled across the post, they found it interesting, they thought it would be good

I think it's just interesting to a lot of the HN audience. A modal HN reader stumbled across the post, they found it interesting, they thought it would be good to post on HN, and it was. I think it's interesting to the modal HN viewer because although FFTs are pretty neat intrinsically, but most people are exposed to FFTs through sound processing (if they are exposed to Fourier Transforms at all, I don't think they were a required part of the CS curriculum at my university, they were only required for the EE courses), so the application of FFTs to images seems like total magic. The explanation that jpegs use FFTs is ho-hum if you spend a bunch of time doing signal processing at your day job, but there are many intellectually curious developers who spend their day job gluing together CRUD apps.