PNG vs WebP vs AVIF: Which Image Format Should You Actually Use?

Pick any image on any website and there’s a good chance it’s a PNG, a WebP or an AVIF. The old JPEG-vs-PNG debate has quietly become a three-way decision, and the right answer depends less on quality dogma than on what the image is and where it’s going. Here’s the practical version — the same decision rule we apply when we ship images ourselves.

The 30-second history

• PNG (1996) — the lossless workhorse. Every pixel survives compression untouched, 8-bit transparency is flawless, and every device and program made this century can open one. Its weakness: lossless compression of photographic content is bulky.
• WebP (Google, 2010) — designed to shrink web images. It has a lossy mode (based on the VP8 video codec) and a lossless mode, both supporting transparency. Safari held out until version 14 (2020), which was the last real compatibility barrier; today it’s safe everywhere.
• AVIF (the Alliance for Open Media, 2019) — a still-image spinoff of the AV1 video codec. It compresses harder than anything before it, supports 10/12-bit color and HDR, and reached practical browser coverage (Chrome, Firefox, Edge, Safari 16.4) in 2023. Its costs are slower encoding and an ecosystem that’s still maturing.

How they compare where it matters

	PNG	WebP	AVIF
Compression	Lossless only	Lossy + lossless	Lossy + lossless
Transparency	Yes (alpha)	Yes (both modes)	Yes
Typical photo size vs JPEG	2–3× larger	25–34% smaller	40–50% smaller
Color depth	8-bit (24-bit RGB)	8-bit	8/10/12-bit, HDR
Encode speed	Fast	Fast	Slow (often 5–10× PNG)
Browser support	Universal	Universal since 2020	Chrome/Firefox/Edge/Safari 16.4+
Non-browser ecosystem	Universal	Good, growing	Patchy
Animation	No (that’s APNG)	Yes	Yes

The “photo size” row is the headline: converting a typical JPEG photo to WebP shrinks it by roughly a quarter, and to AVIF by roughly half, at the same visual quality. For a site serving thousands of images, that difference is measured in dollars of bandwidth and fractions of a second of load time.

The decision rule we use

1. Screenshots, logos, line art, anything with sharp edges → PNG or lossless WebP. Lossy formats smear the flat colors and crisp edges of interface graphics — you’ve all seen the “fuzzy” screenshot. PNG keeps text pixel-perfect. If file size matters and the destination accepts WebP, lossless WebP beats PNG by 20–30% with identical fidelity.

2. Photographs going to the web → WebP, or AVIF if you control the pipeline. Nobody should ship a photograph as PNG on a website; it’s often 5–10× larger than a well-made WebP at visually identical quality. WebP is the safe default with universal support. AVIF squeezes further and handles gradients (sunsets, skin tones) with fewer artifacts, but slow encoding means you’ll want to convert once at publish time, not on the fly.

3. Photos being edited or archived → PNG (or keep the original format). PNG is the safe interchange format for editing: lossless means you can re-open and re-save without generation loss. Never archive a master copy in a lossy format.

4. Email attachments, upload forms, older software → JPEG or PNG. Support beats efficiency wherever an unknown receiver is involved. AVIF files bounce off plenty of upload forms today the way WebP did a decade ago.

The compatibility caveat, honestly

Browser support is not the whole ecosystem. WebP opens in every OS image viewer worth the name. AVIF support outside browsers is spottier: Windows needs a codec pack from the Store (modern builds have it), macOS Sequoia+ handles it in Preview and Quick Look, but plenty of third-party apps and CMS plugins still can’t decode it. The pattern repeats HEIC’s history: the format works in modern software, and old software grumbles.

That’s why the pragmatic workflow for publishing is: keep masters in PNG (or the original format), publish derivatives in WebP/AVIF. Converting is cheap and local — our PNG to WebP and PNG to AVIF converters run the encoders in your browser, so a folder of originals never leaves your machine while you generate both derivatives. When you need to go back — an AVIF that some tool won’t accept, a WebP you want to edit — WebP to PNG gives you a lossless working copy, and the format guide for PNG covers the spec details.

What about JPEG XL?

You’ll occasionally see JPEG XL (JXL) mentioned as the heir to everything: lossless better than PNG’s, lossy better than AVIF’s, plus the killer feature of bit-exact JPEG transcoding. It’s technically excellent. It’s also not in Chrome or Safari, which for web publishing means it’s currently a format for archivists, not for shipping pages. We cover it in the JXL format guide if you’re curious; the honest summary is “watch, don’t adopt yet”.

FAQ

Is WebP quality worse than JPEG?

No — WebP at the same file size looks better than JPEG, or the same quality at a smaller size. Early WebP bad press came from aggressive encoders a decade ago. Modern encoders are mature; artifacts only appear when you push quality settings very low.

Why is my PNG file so huge?

Because PNG is lossless and photos are noisy. A 12-megapixel photo has millions of subtly-different pixels that lossless compression must describe exactly — that’s expensive. A screenshot of a flat-color app window compresses beautifully as PNG; a photograph of a forest does not. Convert the photo to WebP instead.

Can I use AVIF as my only web image format?

Today, safely no — browsers are there, but upload pipelines, email clients and tooling aren’t. Serve WebP (or JPEG) as a fallback alongside AVIF, which is exactly what modern <picture> markup is for. If your audience is 95% modern-Chrome (some internal dashboards are), AVIF-only is defensible.

Does converting PNG to WebP lose quality?

In lossless WebP mode, never — the decoder reconstructs the exact same pixels. In lossy mode, yes, the same way JPEG does. Most “PNG to WebP” tools default to lossy; ours lets you pick, and for graphics with text or transparency we recommend lossless.