How to Convert PNG to WebP and Why It Matters for Your Website

If you have run a Google Lighthouse audit or PageSpeed Insights test on your website recently, you have probably seen this recommendation: "Serve images in next-gen formats." The suggestion is almost always to convert your PNG and JPEG images to WebP.

This guide explains the technical reason PNG-to-WebP conversion matters, how significant the file size savings are in practice, and how to do the conversion for free without installing any software.

What is WebP and Why Did Google Create It?

WebP is an image format developed by Google, first released in 2010. It was specifically designed to replace both JPEG and PNG as the primary image format on the web by achieving better compression than either format while maintaining comparable visual quality.

Google's motivation was simple: images account for approximately 50–75% of a typical webpage's total byte size. A format that achieves 25–35% better compression than JPEG — without any perceptible quality loss — translates directly into faster page loads, lower data costs for mobile users, and better Core Web Vitals scores.

The Technical Difference: How WebP Compresses Better

PNG uses the DEFLATE algorithm, which is excellent for images with large areas of flat colour or repeating patterns (like logos and screenshots) but struggles with the continuous tonal variations in photographs.

WebP's lossy mode uses a compression technique based on VP8 video frame encoding with predictive coding. Instead of encoding each block of pixels independently, it predicts the value of each pixel based on its neighbours and only encodes the difference (the prediction error). Large uniform areas — like clear sky, skin tones, or background colours — are predicted almost perfectly, requiring very little data to encode.

The result: a WebP image at 80% quality is typically:

• 25–34% smaller than an equivalent JPEG at the same visual quality
• 26% smaller than an equivalent lossless PNG (for the same image in lossless WebP mode)
• Equal or better visual quality at the same file size

Real-World File Size Examples

Here are actual conversion results from images processed through ImageFix:

These savings are cumulative. If your website has 30 product images, converting them all from PNG to WebP could reduce your total image payload from 33MB to under 7MB. This has a profound effect on page load times, especially on mobile connections.

Browser Support: Is WebP Safe to Use?

In 2020, Apple finally added WebP support to Safari 14. That was the last major holdout. Today, WebP is supported by:

• Chrome (all versions since 2014)
• Firefox (all versions since 2019)
• Safari (all versions since v14, released September 2020)
• Edge (all versions since 2019)
• Opera (all versions since 2013)
• Chrome for Android ✅
• Safari on iOS ✅ (since iOS 14)

Combined browser market share coverage: 97%+ globally.

The only users who cannot see WebP images are those using very old browsers (Internet Explorer 11, Safari 13 or older). If you are building for a general audience, you can safely use WebP without a fallback in 2026.

If you are building for enterprise clients where IE11 must be supported, use the HTML <picture> element to serve WebP to modern browsers with a PNG fallback.

How to Convert PNG to WebP (No Software Required)

Our browser-based converter handles PNG to WebP conversion in three steps:

1. Upload your PNG — drag and drop it onto the tool
2. Adjust quality — the default 80% is optimal for most images; use 90%+ for logos or text-heavy images
3. Download the WebP — the file is generated locally in your browser and downloaded directly

No account. No upload. No waiting for a server. The entire conversion uses the HTML5 Canvas API running in your own browser, so your files remain completely private.

Using WebP in Your Website

Next.js

Next.js automatically serves WebP via its Image component. Simply use <Image src="/photo.png" /> and Next.js will convert and serve WebP to browsers that support it, with PNG as a fallback.

Static HTML Websites

Use the <picture> element for maximum compatibility:

<picture>
  <source srcset="/image.webp" type="image/webp" />
  <img src="/image.png" alt="Description" />
</picture>

WordPress

Install a plugin like ShortPixel, Imagify, or WebP Express. These automatically convert your uploaded images to WebP and serve them using the <picture> element.

React/Vue/Other Frameworks

Convert your static assets manually and import the .webp files. For dynamically loaded images, use the <picture> element as shown above.

When NOT to Use WebP

Despite its advantages, WebP is the wrong choice in some scenarios:

• Email images: Most email clients (including Outlook) cannot display WebP inline
• Government/institutional portals: These almost universally require JPEG or PNG
• Print production: Print workflows expect TIFF or high-quality JPEG
• When you need AVIF instead: For cutting-edge performance, AVIF achieves even better compression than WebP, though browser support is still slightly less universal (91%+)

For these cases, use JPG (for photos) or PNG (for graphics with transparency) and convert with our other tools.