PNG to WebP: the cheapest speed win on your website

2026-09-05

You run a speed test on your site and the report points at images. The culprits are usually PNGs — screenshots in a help article, a hero graphic, product images exported "safe" from a design tool. They look fine; they just weigh five times what they need to.

Why PNG is heavy on the web

PNG is lossless: it promises every pixel back exactly, and pays for that promise in bytes. That is the right trade for a logo master file. It is the wrong trade for an image that will be looked at in a browser at screen resolution, where a well-encoded lossy version is visually identical and far smaller.

What WebP gives you

• Smaller files at the same visible quality — that is the format's entire purpose.
• Transparency survives. Unlike JPG, WebP has an alpha channel, so a PNG logo or cut-out converts without growing a white box. This is the reason to pick WebP over JPG for graphics.
• Universal browser support — every current browser displays WebP.

Our PNG to WebP converter does the re-encode in your browser, a folder at a time, with a quality slider. Nothing is uploaded.

Where WebP is the wrong choice

WebP is a format for the web. Files you send to other people — clients, print shops, upload forms — still meet software that refuses it, which is exactly the problem our WebP-to-JPG post exists for. Convert to WebP for pages you publish; keep JPG or PNG for files you hand around.

One browser-specific honesty note: Safari cannot save WebP from a canvas. If you convert on Safari, the result falls back to PNG and the file is named to match its real format — no silent lying in the extension. For WebP output, use Chrome, Edge or Firefox.

What we deliberately don't do

We don't resize behind your back to inflate the savings number. A 2400-pixel screenshot converted to WebP is still 2400 pixels; if it is displayed at 800, the bigger win is resizing it first and converting second.

The short version

• PNGs of screenshots and graphics are usually a page's heaviest files.
• WebP keeps transparency and cuts the weight — the right target for published pages.
• Keep JPG/PNG for files you send to other people and their older software.
• Resize to display size first; converting second compounds the saving.