“Unraveling the JPEG” is a great deep dive into the JPEG image format.
This article is about how to decode a JPEG image. In other words, it’s about what it takes to convert the compressed data stored on your computer to the image that appears on the screen. It’s worth learning about not just because it’s important to understand the technology we all use everyday, but also because, as we unravel the layers of compression, we learn a bit about perception and vision, and about what details our eyes are most sensitive to.
Comes with interactive editors which allow you to adjust the JPEG data, and directly see how it affects the image.
Great stuff to play with!