Three formats can hold the same picture on the modern web, and the right one depends on a question most guides skip: what is the image, and where is it going? PNG, WebP, and AVIF each win somewhere and lose somewhere, and by the end of this comparison you will pick between them in seconds. Every conversion mentioned runs free in your browser, starting with the workhorse, our PNG to WebP converter.
In this guide
The three contenders in one paragraph each
PNG (1996) is the lossless veteran: every pixel exact, full transparency, opens absolutely everywhere, and pays for all that with the largest files of the three, especially for photographs, which it was never designed to carry.
WebP (2010) is the modern generalist: lossy mode that runs roughly a quarter to a third smaller than JPEG at comparable quality, a lossless mode that usually beats PNG, plus transparency and animation in one format. Every current browser supports it, which made it the de facto web default; its full story is in our WebP guide.
AVIF (2019) is the compression champion: at comparable quality its files commonly run around half the size of JPEG, and it shines brightest exactly where others fall apart, low bitrates and smooth gradients. Browser support is now universal among current versions, but it is the youngest of the three, and the fine print below is mostly about it.
The comparison table
| PNG | WebP | AVIF | |
|---|---|---|---|
| Compression | Lossless only | Lossy + lossless | Lossy + lossless |
| Photo file size | Very large | Small | Smallest |
| Transparency | Yes, full alpha | Yes | Yes |
| Animation | No (APNG is niche) | Yes | Yes |
| Opens everywhere, including old software | Yes | Browsers yes, old apps mixed | Browsers yes, elsewhere youngest |
| Encoding speed | Fast | Fast | Slow |
The decision, by use case
- Photos on a website you control: AVIF if your pipeline can encode it, WebP as the dependable default. Either beats JPEG and crushes PNG.
- Logos, screenshots, UI graphics: lossless WebP for the web, PNG when the file must also open in arbitrary software. Lossy formats ring around sharp edges, as the compression guide shows.
- Anything needing transparency: all three carry alpha; the choice falls back to the photo-vs-graphic and compatibility questions above. The mechanics live in the transparency guide.
- Files leaving the web: attachments, documents, print, government portals: PNG (or JPEG for photos). Maximum compatibility is the entire requirement, and the veteran wins it.
- Email and messaging: JPEG and PNG still travel safest; a WebP attachment can still confuse an older mail client even though every browser reads it.
The honest fine print
- AVIF encodes slowly. The spectacular compression costs real CPU at creation time, which matters for bulk conversions and matters not at all for a one-off.
- Size advantages are ranges, not constants. “Quarter smaller” and “half of JPEG” are typical mid-quality photo results; sharp graphics, extreme quality settings, and unusual content move the numbers in both directions. Convert your actual image and compare; it takes seconds.
- Recompression is still recompression. Converting a JPEG to AVIF re-encodes already-lossy data; the result is smaller, not better. Convert from the best original you have.
- PNG is not obsolete. It remains the interchange format, the one every tool on earth opens, and the right answer whenever that property is the requirement.
Converting between them
All client-side, no uploads: PNG to WebP and JPG to WebP for the everyday wins; PNG to AVIF and JPG to AVIF for maximum shrinkage; WebP to PNG for the return trip when compatibility calls. The broader format landscape, JPEG, GIF, HEIC and the rest included, is mapped in the image formats pillar.
Frequently asked questions
Should I convert my whole site’s images to AVIF?
If your stack can serve format fallbacks (the HTML picture element exists for exactly this), AVIF-with-WebP-fallback is the current best practice. If you want one format and no machinery, WebP alone captures most of the win with none of the fuss.
Is WebP lossless really smaller than PNG?
Usually, often by a meaningful margin, with identical pixels. The exceptions are rare image types where PNG’s filters happen to fit; comparing your actual file settles it instantly.
Why does my AVIF look better than JPEG at the same size?
Because that is the format’s specialty: at equal bytes, AVIF keeps more visible quality, especially in gradients where JPEG bands. Same-size comparisons are where the generational difference is most visible.
What about JPEG XL?
Technically impressive and, as of now, without the universal browser support the three formats here enjoy. For files that must work for everyone today, it is not yet on the menu, which is the only question this guide answers.