PNG vs WebP: Should You Switch? A Deep-Dive Comparison

WebP is a modern image format developed by Google and released in 2010 with a clear mission: deliver smaller file sizes than JPG and PNG while maintaining equivalent visual quality. Browser support is now mature, and adoption is growing steadily across the web. But PNG’s thirty-year track record reflects real strengths that a newer format has not made entirely obsolete. This guide compares the two in depth so you can decide whether switching makes sense for your situation.

WebP’s Compression Advantage

Google’s own benchmark data shows that lossless WebP is on average 26% smaller than equivalent PNG files; lossy WebP beats JPG by 25–34% on average. These are not marginal gains—they represent a meaningful reduction in bandwidth and storage requirements.

WebP’s compression technology derives from the VP8 video codec and uses more advanced predictive coding and entropy coding algorithms than PNG’s DEFLATE compression. The result is smaller output for both photographic and graphical content.

Images typically account for 50–70% of a web page’s total data weight. Switching your image library to WebP can meaningfully reduce Largest Contentful Paint (LCP) time, improving your Google Core Web Vitals scores and, by extension, your search rankings.

Transparency Support

WebP fully supports Alpha channel transparency, matching PNG’s capability in this regard. You can use WebP images with transparent backgrounds and the visual result is virtually indistinguishable from PNG—just smaller.

This is an important point because many people assume WebP only works like JPG. In fact, WebP has two distinct modes:

• Lossless WebP: Designed to replace PNG. Supports transparency, no quality loss.
• Lossy WebP: Designed to replace JPG. Does not support transparency, but achieves extreme compression ratios.

Current Browser Compatibility

As of 2024, WebP enjoys global browser support exceeding 97%, covering:

• Chrome (supported since 2011)
• Firefox (supported since 2019)
• Safari (supported since iOS 14 / macOS Big Sur in 2020)
• Edge (supported since 2018)

The one notable exception is Internet Explorer, which has no WebP support. However, Microsoft officially ended IE support in June 2022. Unless your target audience includes IE users in legacy enterprise environments, IE compatibility is no longer a practical barrier for most websites.

When to Stick with PNG

Despite WebP’s compression advantages, PNG remains the better choice in certain scenarios:

• Design source files and asset libraries: Native WebP support in design tools such as Photoshop and Figma is still inconsistent. PNG remains the industry standard for editable source assets.
• Print and publishing workflows: Print pipelines typically require PNG, TIFF, or other lossless formats. WebP has limited acceptance in professional print contexts.
• Email images: Many email clients—most notably Outlook—do not render WebP. Images in HTML newsletters and marketing emails should remain PNG or JPG.
• Legacy system integrations: If your platform or partners have specific format requirements, verify WebP acceptance before committing to a migration.
• Screenshots: Operating system screenshot tools output PNG by default. Converting screenshots to WebP is rarely necessary or worth the effort.

Real-World Size Comparison

Approximate size differences across common use cases:

• 1200×800 product photo: PNG ~800 KB → lossless WebP ~580 KB (27% smaller)
• Transparent logo at 400×400: PNG ~45 KB → lossless WebP ~32 KB (29% smaller)
• Full-color illustration: PNG ~1.2 MB → lossless WebP ~880 KB (27% smaller)

For high-traffic websites, this adds up quickly. A site serving 100,000 image requests per month could save tens of gigabytes of bandwidth by switching to WebP.

Implementing WebP on Your Website

The safest approach is to use the HTML <picture> element, which lets you offer WebP with PNG as a fallback:

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

Browsers with WebP support load the WebP version; browsers without support automatically fall back to PNG. This approach gives you the performance benefits of WebP for the vast majority of users while maintaining compatibility for the rest.

WordPress 5.8 and later supports WebP uploads natively. Popular image optimization plugins—including ShortPixel, Smush, and WebP Express—can automatically convert your existing image library and serve WebP to compatible browsers.

Conversion Tools

• Online converters: The easiest option—upload a PNG, download a WebP, no software required.
• ImageMagick (command line): Ideal for batch-converting large image libraries.
• Squoosh by Google: Free browser-based tool with real-time previews of different formats and compression settings.
• Photoshop / Figma: Recent versions support direct WebP export.

Verdict: Is It Worth Switching?

The answer is yes if:

• You are actively optimizing web performance and Core Web Vitals scores.
• Your target audience uses modern browsers.
• You serve large volumes of images to end users.

PNG retains its place in design workflows and email contexts. The most practical strategy is: use WebP for web delivery, keep PNG for design assets and email. With the <picture> element, you do not even have to choose—you can serve both and let the browser decide.

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