alt Hacker NewsIt probably used pixel-by-pixel conversion (decode input format -> encode output format), which is lossy, not the libjxl native way to convert JPEG (it needs to know about the original JPEG data, not the raw image data).
It probably used pixel-by-pixel conversion (decode input format -> encode output format), which is lossy, not the libjxl native way to convert JPEG (it needs to know about the original JPEG data, not the raw image data).