What Is WebP and Should You Switch?

WebP shows up everywhere now: in browser download menus, in your CMS media library, and in performance audits nagging you to "serve images in next-gen formats." But what actually is it, and does switching your images over make sense? Here's the honest version.

What WebP actually is

WebP is an image format created by Google, derived from the VP8 video codec and documented openly. Its whole reason for existing is efficiency: it stores the same picture using fewer bytes than the formats it replaces. It does this with smarter compression techniques than JPEG's decades-old approach (better prediction of neighbouring pixels, better entropy coding) and it supports two modes:

• Lossy: like JPEG, it discards some detail to shrink the file. You trade a little fidelity for a lot of savings.
• Lossless. Like PNG, it keeps every pixel exactly, but still packs them more tightly than PNG does.

Crucially, WebP also supports transparency (an alpha channel) in both modes. That's the feature that makes it a genuine one-format replacement for both JPEG and PNG, rather than just one of them.

Why people switch

The pitch is simple: smaller files. Google's own compression study measured lossy WebP files at 25–34% smaller than comparable JPEGs, and in my experience converting real-world photos, that range holds up: sometimes better, when the source JPEG was encoded conservatively. Against PNG for photographic content, the difference is dramatic.

Smaller images mean:

1. Faster page loads, because the browser downloads fewer bytes.
2. Better Core Web Vitals, since your largest image often is your Largest Contentful Paint.
3. Lower bandwidth costs, which matters at scale and for mobile visitors on metered data.

When WebP is the obvious win

• Website and app imagery. Every current browser supports WebP (97%+ of global traffic), so hero images, thumbnails and product shots are ideal candidates.
• Photos with transparency. WebP gives you PNG-style transparency without PNG-sized files.
• Anything where page speed is a goal. If you're chasing a Lighthouse score, this is low-hanging fruit.

When to think twice

WebP isn't a universal answer. Skip it, or keep an original, when:

• You're handing a file to legacy software: some older desktop apps and enterprise systems still won't open .webp. (This is the snag people actually hit; here's the current support landscape.)
• You need a print-ready or archival master. Keep a lossless PNG or TIFF as your source of truth and export WebP as a delivery copy.
• The image is a tiny flat icon where an SVG would be smaller and sharper anyway.

So, should you switch?

For anything that lives on the web, the answer is usually yes, switch your delivery images to WebP and keep your originals safe. The savings are real, the support is universal, and the downside is limited to a handful of legacy tools you can convert back out of at any time. When you're ready to do it properly across a site, the step-by-step conversion workflow covers fallbacks and serving.

If you want to try it on your own images without uploading anything, our WebP Converter encodes PNG and JPG to WebP right in your browser. It runs Google's own libwebp codec compiled to WebAssembly, so the output matches what a server-side pipeline would produce, and shows you the exact bytes saved. Because switching should never be a one-way door, the same tool decodes WebP back to PNG or JPG whenever you need broad compatibility again.

The best way to decide is to convert a couple of your real images, compare the sizes, and look at the result. If it's meaningfully smaller and still looks right, you have your answer.

Sources

• An image format for the Web (Google WebP documentation)
• WebP compression study (Google)
• WebP browser support (caniuse.com)