Why PNG files are so big, and what AVIF does about it
PNG is lossless. Every pixel is stored exactly, using Deflate compression from the 1990s. That's perfect for a logo you'll edit again, and terrible for a 2000-pixel screenshot or a photo someone exported as PNG. Those files run into megabytes.
AVIF is lossy. It compresses the image with AV1, a video codec (compression method), and throws away detail your eye won't miss, so the same picture lands in a fraction of the space. It also keeps transparency, which is the one thing that stops most people converting PNGs to JPG. The biggest savings come from PNGs that hold photos, gradients or large screenshots. A tiny flat icon with four colours is already small as a PNG and may not shrink much.
How to convert PNG to AVIF
- Drop up to 5 PNG files into the box above. Each can be up to 300 MB.
- AVIF is the preset target. Press Convert. The file is uploaded to our server and encoded there.
- Download the .avif file.
There's no quality slider, and no lossless option. The converter chooses the settings. AV1 encoding is slower than PNG or WebP encoding, so a very large image, around 24 megapixels and up, takes a few seconds. Typical screenshots and web graphics finish quickly.
Transparency survives, with one thing to check
A transparent PNG becomes a transparent AVIF. AVIF stores the transparency as a separate layer inside the file, and browsers that display AVIF show it. Soft edges, drop shadows and half-transparent overlays carry across, not just hard cut-outs.
The thing to check is the edge. Because the output is lossy, the colour pixels along a transparent edge are compressed too, and on a logo with very thin lines you may see faint fringing at 100% zoom. On product cut-outs and UI graphics it's rarely visible. If it bothers you, keep the PNG for that one image.
Convert transparent graphics from the PNG, never from a JPG. JPG has no transparency, so a logo that passed through JPG has a white or black box baked in that no converter can remove.
What changes in the file, and what to watch
- Lossless becomes lossy. The AVIF is not a pixel-exact copy. Keep the PNG as your editing master.
- Small text can soften. Screenshots with 10-pixel UI text are the hardest case for any lossy codec. View the AVIF at 100% before replacing the PNG in a tutorial or documentation page.
- Size limits are not a problem. The AVIF format allows images far larger than any screenshot, unlike WebP, which stops at 16,383 pixels on a side.
Browser support
Every current major browser shows AVIF with its transparency (Chrome from 85, Firefox from 93, Safari on iPhone from iOS 16 and Safari 16.4 on Mac, Edge from 121, Samsung Internet from 14); the full table with release dates is on the JPG to AVIF page.
Serve the AVIF first and the PNG as the fallback
Keep the PNG on the server and list it last. A browser works down the sources inside a picture element and stops at the first type it can decode, so an old Edge build gets the PNG and never sees a broken image:
<picture>
<source srcset='logo.avif' type='image/avif'>
<source srcset='logo.webp' type='image/webp'>
<img src='logo.png' alt='Describe the image' width='600' height='200'>
</picture>The WebP line is optional. It catches Safari 14 and 15 and Edge 18 to 120, which have WebP but not AVIF. Make it from the same PNG with PNG to WebP. Google has indexed AVIF in Image Search since August 2024, and Google's page-speed report, Lighthouse, stops flagging the image in its "Improve image delivery" check (called "Serve images in next-gen formats" in older versions) once the AVIF or WebP version is what the browser actually receives.
The PNGs that gain the most here are the ones that were never photos: logos on a transparent background, icons and UI graphics, and screenshots full of text. Sites keep those as PNG for the clean edges and the transparency, and each one can weigh hundreds of kilobytes. As AVIF they keep the transparency and lose most of the weight. The one check is a screenshot with small text, which you should view at 100% before swapping it in.
When to keep the PNG instead
AVIF is a delivery format, not a working format. Keep the PNG when the image will be opened in a design tool, sent to a printer, or uploaded somewhere that lists PNG but not AVIF. Keep it for favicons and app icons, which need PNG or ICO. And keep it for pixel-perfect screenshots in bug reports, where a lossy copy can hide the thing you're trying to show.
If the PNG is only big because it holds a photo with no transparency, PNG to JPG gives you a file that opens absolutely everywhere, at the cost of a somewhat larger size than AVIF. Every format we can make from a PNG is on the PNG converter page, and everything that becomes AVIF is on the AVIF converter page.