WebP vs PNG
WebP vs PNG: smaller files vs universal support, and when lossless WebP is worth the compatibility tradeoff.
Last updated
The short answer
WebP produces meaningfully smaller files than PNG at equivalent quality, in both lossy and lossless modes, and every browser still in meaningful use supports it — so for web images it's the better default. PNG stays the safer choice for images that travel outside the browser: design files, print pipelines, or any app you don't control that might not read WebP.
| Dimension | WebP | PNG |
|---|---|---|
| File size | 20-30% smaller at same quality | Larger, especially lossless |
| Transparency | Alpha channel supported | Alpha channel supported |
| Animation | Supported (replaces animated GIF) | Not supported |
| Lossy mode | Available, smaller than JPEG too | Lossless only |
| Compatibility | All modern browsers; older tools may choke | Universal, decades of support |
Choose WebP when
- →You're serving images to a browser and want smaller payloads without a visible quality hit — the default case for most sites now.
- →You need transparency AND smaller file size at once; WebP beats PNG at both lossy and lossless compression.
- →You have simple animations and want to drop animated GIF's huge file size and limited color palette.
Choose PNG when
- →The file needs to open reliably outside a browser — design tools, older image editors, print workflows, email clients.
- →You're generating assets programmatically (screenshots, charts, favicons) for pipelines that expect PNG specifically.
- →Pixel-perfect lossless output matters and you can't risk a downstream tool mishandling WebP.
The catch nobody mentions
'WebP is smaller' assumes you're comparing against an unoptimized PNG — a PNG properly run through a modern optimizer (pngquant, oxipng) closes much of the gap, and for images with large flat color areas the difference can be small. Benchmark your actual images before assuming the swap saves as much as the marketing claims.
Questions
Is WebP lossless as good as PNG?
Better, typically — Google's figure is around 26% smaller for equivalent lossless images, and independent tests broadly agree. WebP also supports lossy compression with transparency, which PNG cannot do at all.
Is browser support still a concern?
No. Every current browser supports WebP, including Safari since 2020. The remaining gaps are older email clients and some design tools, which is why a PNG fallback still appears in newsletters.
When is PNG still the right choice?
When something outside a browser has to open the file — a print workflow, a partner's system, an email client — or when you need the widest possible compatibility with no negotiation. Universality is the feature PNG still owns.
What about AVIF?
It compresses better again, particularly on photographs, with support in all current browsers. Encoding is considerably slower, so it suits assets built once and served many times rather than user uploads processed on the fly.
How do I serve both?
A picture element with a WebP source and a PNG fallback lets the browser choose, and needs no server logic. Content negotiation on Accept does the same thing centrally if you would rather not change the markup.
Does converting an existing PNG lose quality?
Not with lossless WebP — the pixels are identical and only the encoding changes. Converting to lossy WebP does lose data, and re-encoding an already-lossy source compounds it, so always convert from the original.