If your website feels slow, there's a good chance your images are to blame. PNG is everywhere — screenshots, logos, UI mockups, product shots — but it's often the heaviest format you can ship to a browser. The fix is usually simple: convert your PNGs to WebP.
WebP is a modern image format from Google that produces dramatically smaller files than PNG while keeping the same visual quality. In this guide you'll see exactly how to convert PNG to WebP for free, how much you'll save, and when WebP is (and isn't) the right choice.
Why PNG files are so large
PNG uses lossless compression. Every single pixel is preserved perfectly, which is great for crisp logos and screenshots — but terrible for file size when the image has lots of colors or photographic detail. A full-color PNG screenshot can easily weigh 1–3 MB.
That weight matters. Page weight directly affects:
- Load time — every kilobyte has to travel down the wire.
- Core Web Vitals — especially Largest Contentful Paint (LCP), a Google ranking signal.
- Mobile data — your visitors on phones pay for every byte.
What makes WebP better
WebP supports both lossless and lossy compression, plus transparency (an alpha channel) just like PNG. The headline benefit is size:
- WebP lossless images are typically 26% smaller than PNG.
- WebP lossy images are often 25–35% smaller than comparable JPEG.
For a PNG screenshot, dropping to WebP often cuts the file by 60–80% with no visible difference. Browser support is now universal — every modern browser, including Safari, renders WebP.
How to convert PNG to WebP for free
You don't need Photoshop or a command-line tool. The fastest way is to use the free Image Converter, which runs entirely in your browser — your files are never uploaded to a server.
- Open the Image Converter.
- Drag in your PNG (or several at once).
- Choose WebP as the output format.
- Adjust the quality slider if you want to trade a little fidelity for an even smaller file.
- Download your converted WebP.
Because everything happens locally on your device, conversion is instant and completely private — perfect for screenshots or unreleased designs you don't want sitting on someone else's server.
Want even smaller files?
If your PNG is also bigger than it needs to be on screen, resize it first with the Image Resizer. Shrinking a 4000px-wide image down to the 1200px you actually display, then converting to WebP, compounds the savings. For photos you want to keep as JPEG or WebP at a target size, the Compress Image tool lets you dial in exactly the file size you need.
When to keep PNG instead
WebP wins most of the time, but PNG still has a place:
- Tiny icons and simple graphics where the difference in size is negligible.
- Email — some older email clients still don't render WebP.
- Assets for software that explicitly requires PNG (favicons, app stores, certain CMS uploaders).
For favicons specifically, use the dedicated Favicon Generator which outputs the exact PNG sizes browsers expect.
A quick before/after checklist
Before you ship images to production:
- Is the image larger than it's displayed? Resize it.
- Is it a screenshot or full-color graphic? Convert to WebP.
- Is the file still heavy? Lower the quality slightly — WebP holds up well.
- Re-test your page in your browser's dev tools to confirm the smaller payload.
FAQ
Does converting PNG to WebP lose quality? With lossless WebP, no — it's pixel-perfect and still smaller. With lossy WebP you can choose the quality; at 80–90% most images look identical to the original.
Is it safe to convert private screenshots? Yes, when you use an in-browser tool like the Toolmingo Image Converter. Your files are processed locally and never uploaded.
Will WebP work in all browsers? Yes. Every current browser — Chrome, Edge, Firefox, Safari and their mobile versions — supports WebP.
Converting your PNGs to WebP is one of the highest-impact, lowest-effort things you can do for site speed. Start with your heaviest images, run them through the Image Converter, and watch your page weight drop.