Why JPEGs still rule the web (2024)

Original Article ↗ Hacker News Discussion ↗

Why JPEG Still Dominates

  • Patent‑free, universally supported, “good enough” quality, and extremely fast to encode/decode. Hardware and software JPEG decoders are trivial compared to newer formats.
  • Huge existing corpus means everyone must support JPEG anyway; once you must keep it for compatibility, many see little benefit in switching for new images.
  • Ongoing encoder improvements (mozjpeg, jpegli) squeeze another ~5–15% compression and better perceptual quality out of the same old bitstream, narrowing the value of new formats.

WebP: Technically Fine, Socially Fractured

  • Some report that on modern Windows and Linux desktops WebP “just works” (Explorer, Paint, GIMP, etc.).
  • Others say “nothing supports WebP”: many upload forms reject it, CDNs and thumbnailers don’t handle it, major tools (e.g., Google Docs, some editors, video software) lack full support. GitHub and various web services still don’t accept it natively.
  • Backends frequently auto‑convert user JPEG/PNG uploads to WebP, sometimes re‑encoding lossless inputs to larger, worse lossy WebPs; repeated lossy transcodes cause visible generation loss.
  • Users resent not being able to easily reuse images (presentations, social media, simple viewers), and some have disabled WebP in browsers or resort to screenshots.
  • Security concerns noted: large, complex libwebp codebase has already yielded serious exploits.

AVIF, HEIC, JPEG 2000, JPEG XL

  • AVIF: good compression, but encoders are slow, CPU‑heavy, and can blur fine detail or mishandle dark scenes; support for 10‑bit and 4:4:4 is patchy.
  • HEIC/HEIF: technically solid (HDR, >8‑bit) and widely used by iPhones, but patent‑encumbered and inconsistent in practice (Windows decoding performance, HDR quirks, licensing worries).
  • JPEG 2000: better artifacts than JPEG, used in digital cinema and some archival workflows, but historically patent‑minefield, computationally heavier, poor browser support.
  • JPEG XL: widely praised in the thread as the best all‑round successor (lossless JPEG transcoding, HDR, extra channels, good performance), royalty‑free, supported system‑wide on recent Apple and Windows versions.
    • Chrome added then removed support, officially citing low usage; many commenters see this as Google protecting WebP/AVIF. Firefox is waiting on a safe Rust decoder.

PNG, GIF, and Use‑Case Splitting

  • Consensus: JPEG for photos; PNG (or SVG) for UI, line art, transparency, and exact color; GIF mainly legacy for simple animation.
  • PNG is lossless and ideal where fidelity or sharp edges matter; JPEG’s YCbCr/lossy pipeline makes exact color matching and crisp text harder.

Broader Pattern: “Good Enough” Wins

  • Many compare JPEG to MP3, ZIP, and H.264: technically surpassed but entrenched by ubiquity and tooling.
  • Newer formats (Opus, AV1, JPEG XL, AVIF) often win in labs but face inertia, patents, political battles (especially around Chrome), and fragmented real‑world support.