There is no single best image format. The right choice depends on what the image contains, which features it needs, where it will be displayed, and how much complexity your publishing workflow can support. For the broader decision framework behind that choice — image type, transparency, destination, and fallback strategy — see What Is the Best Image Format for the Web?. This article focuses on a direct side-by-side of the four formats below.

JPEG: dependable for photographs

JPEG is a lossy format built for continuous-tone images. It remains widely accepted by browsers, editors, email clients, content systems, and older software. That compatibility makes it a safe delivery format for photographs.

JPEG does not support transparency. It can also create visible blocks or halos around hard edges, text, and line art when quality is low. Use the JPG compressor for photos, not for every kind of graphic.

PNG: sharp, lossless, and transparent

PNG preserves pixel values without lossy degradation and supports alpha transparency. It is well suited to screenshots, interface graphics, diagrams, and assets with hard-edged transparency.

The trade-off is size. Photographs usually contain too much varied detail for PNG to store efficiently. If a transparent graphic has many colors or photographic regions, compare it with WebP.

Browser PNG encoders also expose fewer tuning controls than JPEG or WebP. Resizing and removing metadata may help, but an already optimized PNG may not shrink.

WebP: a flexible web delivery option

WebP supports lossy and lossless modes plus transparency. It can replace JPEG for many web photos and PNG for some graphics. Current browsers commonly decode it, and capable canvas implementations can encode it locally.

Compatibility outside the browser can still matter. A legacy desktop application or submission portal may demand JPEG. The image converter checks WebP encoding support rather than presenting an option that silently creates another format.

AVIF: strong compression with workflow costs

AVIF can produce excellent results at low file sizes, supports transparency, and benefits modern web delivery. It also has practical costs: encoding can be slower, tuning is less familiar, and support in image-processing paths is not the same as support for simply displaying a file.

That distinction matters in a browser tool. A browser might show AVIF in an <img> element but not offer AVIF through canvas encoding. A WebAssembly library may support AVIF only when its compiled build includes the correct codec. Claims should be based on the actual shipped engine.

ImagesCompressor addresses that gap with a self-hosted WebAssembly AVIF codec that loads only when an AVIF input or output is requested, so pages that never touch AVIF do not pay for it. The AVIF compressor and the JPG to AVIF, PNG to AVIF, and WebP to AVIF converters run a real capability check before enabling AVIF output, and AVIF jobs are processed one at a time to keep memory use predictable. This has been exercised across Chromium, Firefox, and WebKit, but that is not a claim of universal browser support — the tool still disables AVIF output rather than guessing when a browser cannot encode it.

Quick decision guide

  • Choose JPEG for maximum photographic compatibility.
  • Choose PNG for lossless sharp graphics or transparency.
  • Choose WebP for modern web delivery when your workflow accepts it.
  • Consider AVIF when you control the serving pipeline, have tested decoding, and can afford its encoding complexity — the AVIF compressor is a reasonable way to try it against your own files.

For production websites, the <picture> element can offer modern sources with a compatible fallback. Keep the original source, generate delivery variants, and verify that your CDN or build tool labels files with the correct MIME type.

Quality is not portable between formats

A quality value of 80 is not a universal visual target. Encoders interpret quality differently, and different images respond differently. Compare outputs at the intended display size. Look at edges, gradients, skin, fine textures, and transparency boundaries.

Conclusion

Select formats by content and destination, not fashion. JPEG, PNG, and WebP cover most everyday browser workflows. AVIF can be valuable in controlled publishing systems, but it deserves real codec and browser testing before it becomes a promised feature.