JPEG Compression in 2025: Best Practices & New Formats

Updated: 2025-10-18

JPEG has been the workhorse of web imagery for decades, but the landscape is changing. In 2025, designers and developers have a wealth of choices—from modern JPEG encoders that squeeze out every unnecessary bit to next‑generation formats like WebP and AVIF that offer dramatically better compression. This guide explores how to get the most out of JPEG today and when it makes sense to switch formats.

Why care about JPEG compression?

File size still dictates loading speed and user experience. Large images block rendering and inflate bandwidth costs. Studies show that compressing images reduces data transfer and initial load times【413330301302362†L87-L94】. Yet not all compression is equal—choosing the right encoder and tuning quality settings can yield significant savings while maintaining visual fidelity. In 2025, the competition from new formats makes it even more important to understand JPEG’s place.

Modern JPEG encoders

Standard JPEG libraries often leave performance on the table. Tools like mozjpeg and libjpeg-turbo implement advanced techniques such as trellis quantisation, progressive encoding and optimized Huffman tables. These methods can reduce file sizes by up to 10‑20 % compared to baseline encoders without any perceptible quality loss. Progressive JPEGs also improve perceived load time by displaying a low‑quality preview before downloading the full image.

When compressing manually, start with quality values around 75–80 and iterate. Inspect at 100 % zoom to spot banding or noise in smooth gradients. For photographic images with a lot of detail, a slightly higher quality (85) may be necessary, while UI elements can often be compressed to 60–70. Remove unnecessary metadata (EXIF, thumbnails) with tools such as exiftool to shave off additional kilobytes.

Next‑generation formats: WebP and AVIF

If you’re serious about performance, you shouldn’t stop at JPEG. Google’s WebP and the newer AVIF format can yield far better compression. The official WebP study found that WebP files are approximately 25–34 % smaller than equivalent JPEGs at the same structural similarity index【171508693852780†L241-L290】. A 2025 comparison by SpeedVitals notes that WebP images are 25–34 % smaller than JPEG and that AVIF can be ~50 % smaller【221654481411971†screenshot】.

AVIF extends this further. It uses the AV1 video codec’s modern compression algorithms to deliver superior rate–distortion performance. As of September 2025, both WebP and AVIF are widely supported in browsers, although WebP still has a slightly higher adoption rate (about 95 %) compared to AVIF’s 93.8 %【111889046720395†screenshot】. AVIF often requires more processing power to encode and decode but its smaller files can offset the slower decoding times【401814846636866†screenshot】.

Recommended implementation

Use the <picture> element to deliver multiple formats. Serve an AVIF source first, then WebP, and fall back to JPEG. Include explicit width and height attributes to prevent layout shifts and set fetchpriority="high" for critical hero images【483188929336708†L150-L176】.

JPEG in a world of AVIF and WebP

JPEG isn’t dead. It remains a reliable fallback for older browsers and workflows that cannot yet produce AVIF or WebP. It’s also still useful for progressive loading sequences. When using JPEG as a fallback, pair it with a modern encoder and restrict image widths to the maximum size needed on your site. Use responsive image techniques (srcset and sizes) to avoid serving unnecessary pixels to mobile users【483188929336708†L150-L176】.

Actionable best practices

Conclusion

In 2025, JPEG remains relevant but it’s no longer the default choice for performance‑conscious sites. Modern encoders squeeze more out of JPEG, but the biggest gains come from adopting next‑generation formats like WebP and AVIF. By following the practices outlined above—choosing the right encoder, tuning quality settings, stripping metadata and delivering responsive variants—you can provide crisp visuals without sacrificing speed.