Cloudinary Blog

There are two different kinds of JPEG images: progressive JPEGs and non-progressive JPEGs. These categories have nothing to do with the JPEGs’ political beliefs. They’re all about the order in which they’ve been encoded.

In part one (One pixel is worth three thousand words) of this turned-to-be-two-part blog post, I discussed one-pixel images and how well different image formats “compress” these images. I was surprised how much there is to be said about the matter. This was supposed to be a short blog post, describing one-pixel images and how they compress, and instead it became a glorious monster (and also a two part blog post…).

A couple of months ago while taking a break from implementing cool new features like q_auto and g_auto, I was joking in our team chat about how well various image formats “compress” one-pixel images. In response, Orly — who runs the blog — asked me if I’d write a post about single-pixel images. I said: "Sure, why not. But it will be a very short blog post. After all, there’s not much you can say about a single pixel."

If you make a copy of a copy of a copy, the quality will deteriorate with every ‘generation’. This problem is called ‘generation loss’. It is not difficult to understand why this happens with actual copier machines. Scanning and printing are not perfect, being based on noisy sensors and physical paper and ink, and the resulting noise will tend to accumulate.