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PNG vs WebP for Web Images

If you're putting images on a website, you've probably heard that WebP is "better" than PNG. Smaller files, faster loading, better for SEO. It's mostly true—but PNG still has its place.

The Size Difference

WebP files are typically 25-35% smaller than PNG files of the same image. For a website loading dozens of images, that adds up to real speed improvements.

Here's a rough comparison for a typical image:

  • PNG: 500 KB
  • WebP (lossless): 350 KB
  • WebP (lossy, high quality): 150 KB

That last one is the kicker. WebP can do lossy compression (like JPG) while still supporting transparency (like PNG). PNG can't—it's lossless only.

When to Use WebP

  • Website images. Faster load times, better Core Web Vitals scores. This is what WebP was designed for.
  • App assets. Smaller app bundle sizes.
  • Images with transparency that don't need to be lossless. A product photo on a transparent background? WebP can compress it much smaller than PNG.
  • Any situation where file size matters more than maximum compatibility.

When to Use PNG

  • Screenshots and images with text. PNG's lossless compression preserves sharp edges perfectly. WebP can too (in lossless mode), but if you need to share or edit the file later, PNG is more universally supported.
  • Source files for editing. Keep your originals in PNG for editing, export to WebP for the web.
  • When you need guaranteed compatibility. Every image viewer, browser, and app supports PNG. WebP support is widespread now, but not quite universal.
  • Email attachments. Some email clients display WebP fine, others don't. PNG is safer.

Browser Support in 2024

WebP is supported by:

  • Chrome (since 2014)
  • Firefox (since 2019)
  • Safari (since 2020, macOS Big Sur / iOS 14)
  • Edge (since it switched to Chromium)

That covers over 95% of web traffic. The holdouts are older Safari versions (pre-2020) and Internet Explorer (which Microsoft has officially retired). For most websites, you can safely use WebP as your primary format.

If you need to support older browsers, serve PNG as a fallback using the <picture> element.

Quality: Can You Tell the Difference?

For lossless compression, WebP and PNG look identical—both preserve every pixel perfectly. WebP just does it with a smaller file.

For lossy WebP, you're trading some quality for much smaller files. At high quality settings (80-90), most people can't tell the difference without zooming in and comparing side-by-side. Below 70, compression artifacts become noticeable.

The Practical Approach

For websites:

  1. Use WebP as your primary format
  2. For images with transparency, test lossy WebP—you might not need lossless
  3. Keep PNG originals in case you need to regenerate
  4. Consider serving PNG as a fallback for older browsers if your audience needs it

Need to convert? Convert PNG to WebP here or convert WebP to PNG if you need the compatibility.

What About AVIF?

AVIF is even newer and compresses even better than WebP. But browser support is still catching up (no Safari until 2023), and encoding is slower. WebP hits the sweet spot of good compression and wide support. Check our WebP vs AVIF comparison for more details.