I can be quite passionate about image codecs. A “codec battle” is brewing, and I’m not the only one to have opinions about that. Obviously, as the chair of the JPEG XL ad hoc group in the JPEG Committee, I’m firmly in the camp of the codec I’ve been working on for years. Here in this post, however, I’ll strive to be fair and neutral.
When the JPEG codec was being developed in the late 1980s, no standardized, lossy image-compression formats existed. JPEG became ready at exactly the right time in 1992, when the World Wide Web and digital cameras were about to become a thing. The introduction of HTML’s
<img> tag in 1995 ensured the recognition of JPEG as the web format—at least for photographs. During the 1990s, digital cameras replaced analog ones and, given the limited memory capacities of that era, JPEG became the standard format for photography, especially for consumer-grade cameras.
Fidelity in images is about visually preserving the original; appeal is about hiding the compression artifacts. Depending on your priority, you would compress images with either of these approaches to reduce the file size while still maintaining a reasonable level of visual “quality”: