Three formats now cover almost every photographic image on the web: JPG, the thirty-year-old default; WebP, Google's replacement that finally reached every browser; and AVIF, the newest and most efficient of the three. Each earns its place in a different situation, and picking the right one is usually worth a 30–60% reduction in file size at identical visual quality.

The one-paragraph verdict

Use AVIF for images on your own website when you can provide a fallback, WebP when you want one modern format everywhere without thinking about fallbacks, and JPG when the file leaves the web — email attachments, documents, uploads to systems you do not control, or anything a user might open in older software.

JPG: the compatibility king

JPG opens everywhere: every browser, every OS, every photo viewer, every government upload portal, every printer kiosk. Its compression is dated — noticeably larger files than WebP or AVIF at the same quality, no transparency, visible artifacts at aggressive settings — but compatibility is a feature no other format matches. When a form says “photo under 100KB,” the safe answer is a JPG from a tool like our compress JPG to 100KB page.

WebP: the sensible default for the web

WebP typically produces files 25–35% smaller than an equivalent JPG, supports transparency (unlike JPG) at a fraction of PNG's size, and has been supported by every major browser since 2020. Its weakness is life outside the browser: some older desktop software and a surprising number of upload forms still reject.webp files — which is why “convert WebP to JPG” remains one of the most searched image tasks. For images you serve on your own site, that drawback is irrelevant, and converting JPG to WebP or PNG to WebP is one of the easiest page-weight wins available.

AVIF: the efficiency leader

AVIF, based on the AV1 video codec, compresses roughly 20–30% smaller than WebP and up to 50% smaller than JPG at comparable quality. It shines on photographic images with smooth gradients, where JPG banding is most visible, and it supports transparency and HDR. Browser support is now solid — Chrome, Firefox, Safari, and Edge all decode it. The caveats: encoding is slower, very old devices and most non-browser software cannot open it, and at extremely low quality settings it can over-smooth fine texture. Try it on your own images with our image to AVIF converter — the size difference on a typical photo is startling.

What about PNG?

PNG is not a competitor in this comparison — it is a lossless format for a different job: screenshots, logos, UI graphics, and anything needing pixel-perfect edges or transparency in maximum-compatibility form. For photographs it produces enormous files and should almost never be used.

Practical rules of thumb

  • Your own website, maximum savings: AVIF with a WebP or JPG fallback via the <picture> element.
  • Your own website, minimum complexity: WebP everywhere.
  • Email, forms, portals, sharing with others: JPG.
  • Logos, screenshots, transparency with legacy support: PNG.
  • Not sure? Convert the same image to each format and compare — our converter shows a live preview and file size for JPG, PNG, WebP, and AVIF side by side.

How to test the difference on your own images

Benchmarks use other people's photos; your results depend on yours. Screenshots and flat graphics compress differently from portraits, and a format's advantage can shrink or grow by 20 points between image types. The reliable method takes two minutes: take three representative images from your site, export each as JPG, WebP, and AVIF at the same quality setting, and compare the sizes and the look at 100% zoom. Pay attention to gradients (skies, shadows) where JPG bands first, and to fine texture (hair, fabric, foliage) where aggressive AVIF can smooth away detail.

Does the format replace compression?

No — format and quality setting work together. A WebP exported at quality 95 can be larger than a well-compressed JPG at quality 80. Whatever format you pick, spend ten seconds on the quality slider: for most photos, 75–85% quality is visually indistinguishable from the original at half the bytes or better. The combination — modern format plus sensible quality — is what actually makes pages fast, and it is the core of our guide on optimizing images for Core Web Vitals.