libjpeg 6 is pretty good. It's oldschool C so it's pretty spartan, but it's easy enough to read it and follow what it's doing if you have a basic understanding

libjpeg 6 is pretty good. It's oldschool C so it's pretty spartan, but it's easy enough to read it and follow what it's doing if you have a basic understanding of the concepts. (Discrete cosine transform, Huffman coding, etc) And it's only had a couple of vulnerabilities, in nearly 30 years of being on the Internet. That's not quite like DJB code, but it's darn close. My understanding is that it was written by a very small number of people who were experts in the field, as part of the standards process way back in the early 90s.