What changes when a PNG becomes WebP
The table saves three PNG files as lossy WebP at quality 80 and as lossless WebP. The photo went from 3.75 MB to 403 KB, which is 89% smaller. A photo stored as a PNG is the best case for this conversion, because PNG was never built for photographs.
The screenshot is the more useful row. Lossless WebP made it 16 KB, smaller than the lossy version at 29 KB, and lossless keeps every letter sharp. The illustration went the other way: lossy gave 31 KB and lossless 53 KB. As a rule, use lossy for photos and gradients and lossless for flat interface graphics, then check the result in the compare view.
| Test image | PNG | WebP, quality 80 | WebP, lossless | Smaller (quality 80) | Fidelity (PSNR) |
|---|---|---|---|---|---|
| Photo (PNG) | 3.75 MB | 403 KB | 2.75 MB | 89% smaller | 35.7 dB |
| Screenshot | 46 KB | 29 KB | 16 KB | 36% smaller | 44.7 dB |
| Illustration | 94 KB | 31 KB | 53 KB | 68% smaller | 43.5 dB |
The PNG files were already optimised with oxipng, so these gaps are against a good PNG. Lossless WebP can be larger than a well-packed PNG of flat graphics. The illustration keeps its transparency in both WebP variants. Test images are synthetic files made by this project: a 2000 x 1333 landscape photo, a 1600 x 900 interface screenshot and a 1200 x 1200 transparent illustration. Timings: one thread of WebAssembly on Node v22.23.4, Intel(R) Xeon(R) Processor @ 2.10GHz, 2 cores, measured 2026-10-31. Other devices will differ.
Transparency stays
WebP carries an alpha channel, so a logo or a cut-out with a see-through background is still see-through after conversion. The background colour setting only matters if you switch the output to JPEG.
Where WebP works and where it does not
Every current major browser displays WebP, and most CMS platforms and image services accept it. Some email clients, older desktop software, print shops and a few upload forms still want PNG or JPEG. If the destination is one of those, keep the PNG, or go the other way with WebP to PNG.
Settings that matter
- Quality 80 is the default and suits most photos. Lower it for thumbnails.
- The Lossless WebP switch, under Format and quality in Advanced settings, stores every pixel exactly.
- A size target works with lossy WebP: choose 100 KB and the tool finds the quality that fits.
- Colour profiles are removed by default after the browser converts the image to sRGB, so colours look the same. Keep the profile under Metadata in Advanced settings if you need it.
What it leaves out
Animated PNG and GIF files keep only their first frame. Very large images, above 90 megapixels, are refused with a message asking you to resize first.
Using the files on a website
Browsers that support WebP use it with no extra work. If you want a fallback for the few that do not, wrap the image in a picture element with the WebP as the first source and the PNG as the plain img inside, and keep the PNG next to it on your server.
Give the image width and height attributes taken from the result line, so the page does not jump while it loads. The tool shows the pixel size of every result.
Questions
Is WebP better than PNG?
For photos, yes by a wide margin. For flat graphics it depends, which is why the table includes a lossless column.
Will the picture look different?
Lossless WebP is pixel-identical. Lossy at quality 80 is close for most images, and the compare slider lets you check at 100% zoom.
Can I convert many files?
Yes. Drop them together, within the daily limit of 10 images. The <a href="/bulk-image-converter/">bulk page</a> adds a ZIP.
Are my PNG files uploaded?
No. They are converted in this tab.