How to Convert PNG to AVIF in Your Browser

How PNG becomes AVIF

1. The browser decodes the PNG into a full pixel grid, including its alpha channel if the file has one — PNG’s own compression is lossless, so this recovers the exact pixel values that were originally saved.
2. That pixel grid is drawn onto a canvas without any background fill, keeping transparent and semi-transparent areas intact rather than painting over them.
3. The canvas is then encoded as AVIF using the browser’s AV1-based image encoder at your chosen quality setting — a lossy step, since AVIF’s compression discards some information to reach a smaller file.
4. Before the download is offered, the tool verifies the resulting blob is genuinely image/avif rather than a silent fallback format, so you never end up with a mislabeled file.

What changes when you convert

The biggest shift is that lossless becomes lossy. PNG stores every pixel exactly; AVIF’s encoder — even at a high quality setting — makes compression trade-offs the PNG never had. That’s the source of AVIF’s size advantage, and also the reason this conversion isn’t reversible without quality loss.

Transparency generally survives the trip. When the browser’s AVIF encoder supports alpha, which current versions of Chromium-based browsers do, semi-transparent and fully transparent pixels are preserved rather than flattened onto a background color.

File size usually drops, sometimes substantially, but “usually” isn’t “always” — a PNG that’s already small, or one with content that compresses awkwardly under AV1, can occasionally end up larger as an AVIF. Compare the actual output rather than assuming the size will shrink.

When AVIF is the right choice — and when it isn’t

AVIF is worth using when you’re preparing an image for a website or app that already serves modern formats and you want the smallest file that still keeps transparency — icons, illustrations, and UI graphics with alpha channels are good candidates. The savings compound across a page with many images.

It’s the wrong choice when you need the file to keep editing losslessly, since every future re-save re-applies AVIF’s lossy compression. It’s also a poor fit if the destination’s AVIF support is uncertain — plenty of software and older browsers still can’t open an AVIF at all, in which case keeping the PNG, or converting to WebP instead, is the safer bet.

Limitations and privacy

AVIF encoding support in the browser is Chromium-first today — Chrome, Edge, and similar browsers handle it, while others may not expose canvas AVIF encoding at all. When that’s the case, the tool fails clearly with a compatibility message instead of silently saving a different format under an .avif name.

The quality slider (50–100%, default 90%) is the only control over the lossy trade-off; there’s no true lossless AVIF mode in this tool. Conversion runs entirely in your browser, and your PNG is never uploaded to a Looty Tools server.