On iPhone, ProRAW is Apple’s RAW capture format: it combines a full 12‑ or 16‑bit sensor readout (like a traditional RAW/DNG) with Apple’s computational photography, giving you much more latitude for exposure, white balance, and color grading than standard JPEG/HEIF while still saving as a .dng file that many editors can open.
The three JPEG options you’re seeing in the ProRAW settings refer to how the embedded “preview image” inside the DNG is compressed and how the RAW data itself is compressed.
JPEG Lossless
• Uses the older lossless JPEG standard (different from the usual lossy JPEG you’re used to) to compress the embedded image and/or RAW image without discarding data, so decompression reconstructs the original data bit‑for‑bit.
• Most compatible, but larger files and lacks the modern features and efficiency of JPEG XL (more limited color, HDR, and compression efficiency).
JPEG‑XL Lossless
• Uses the newer JPEG XL format in a truly lossless mode, no image information is discarded, but compression is much more efficient than legacy JPEG Lossless, so you get smaller ProRAW files at the same quality.
• Supports wide color and HDR and is designed as a modern replacement for traditional JPEG for archival and editing workflow.
JPEG‑XL Lossy
• Uses JPEG XL in a high‑quality lossy mode. Some data is discarded during compression to shrink file size further, but at intended settings the loss is designed to be visually negligible (perceptually lossless) in normal viewing.
• Gives the smallest ProRAW files while still preserving far more detail and dynamic range than a straight lossy JPEG output, but in extreme edits or heavy crops you may reveal compression artifacts compared to JPEG‑XL lossless.
ProRAW itself is still RAW DNG, this setting is choosing which compression scheme/algorithm (legacy JPEG lossless vs JPEG‑XL lossless vs JPEG‑XL lossy) is used to store that RAW and its embedded preview, trading off compatibility vs compression/file size vs a tiny bit of ultimate edit ability and quality.
JPEG XL Lossless compression preserves every bit of the original image data, resulting in larger files but perfect fidelity for editing. JPEG XL Lossy discards some nonessential data for visually similar results at much smaller sizes, often 40-60% reduction depending on quality settings. Apple’s tests on iPhone 16 Pro (extendable to iOS 26 devices) show clear file size differences for the same scene.
These gains come from JPEG XL’s advanced algorithms, lossy shrinks files by binning pixels selectively while staying high quality for sharing, but lossless retains full detail for post-processing.
