PDFs support j2k, so every PDF renderer includes a j2k decoder. I used this fact for a while because j2k significantly outperforms most JPEG encoders on line-a

PDFs support j2k, so every PDF renderer includes a j2k decoder. I used this fact for a while because j2k significantly outperforms most JPEG encoders on line-art (e.g. comics). I switched back to JPEG recently though as there is now a JPEG encounter that targets high bpp only uses, and is only like 15% larger, while being fire and forget (as opposed to open JPEG, where I needed to adjust the quality factor depending on the source material).