Convert to WebP for a Faster Website

On most websites, images are the single largest contributor to page weight: often more than the HTML, CSS and JavaScript combined. That makes image format the highest-leverage speed change you can make. Converting to WebP is one of the easiest ways to ship fewer bytes without redesigning anything.

Here's the workflow I use on my own sites, start to finish.

Step 1: Find your heaviest images

Before converting everything, find out what's actually slowing you down. Open your browser's DevTools, go to the Network tab, filter by images, and sort by size. The handful of biggest offenders, usually hero banners and full-width photos, are where WebP pays off most.

Focus your effort there first. Converting a 1.8 MB hero image to a 500 KB WebP does far more for your visitors than shaving a few kilobytes off a tiny icon.

Step 2: Convert the images

Take your source PNGs and JPGs and re-encode them as WebP. For each image:

1. Drop the file into the WebP Converter and choose the To WebP direction.
2. Start around quality 80, for most photos that's visually indistinguishable from the original while cutting file size substantially. Google's own WebP study found lossy WebP files 25–34% smaller than comparable JPEGs.
3. Compare the before/after size the tool reports. If it's still heavy, nudge the quality down and convert again.
4. Eyeball the result at full size to confirm it still looks right before you commit.

A note on what's actually doing the work: the converter runs libwebp (Google's reference WebP encoder) compiled to WebAssembly, in your browser. It's the same codec a build pipeline would use on a server. The only difference is that your images never leave your machine, and you can iterate on the quality slider with instant feedback instead of re-running a build.

Step 3: Serve WebP with a safety net

WebP has shipped in every major browser for years now (caniuse.com puts support above 97%), but good practice is still to let the browser pick. The �1� element does exactly that:

<picture>
  <source srcset="/img/hero.webp" type="image/webp">
  <img src="/img/hero.jpg" alt="Product hero" width="1200" height="600">
</picture>

The browser loads the WebP when it can and falls back to the JPG otherwise. You get the savings with zero risk of a broken image. If your site runs on a CDN or image service that auto-negotiates formats, you may only need to upload the WebP and let the Accept header do the rest: check what your host already handles before writing markup.

Step 4: Don't forget the basics

Format is only part of the story. Pair WebP with these and the effect compounds:

• Set explicit width and height so the browser reserves space and avoids layout shift.
• Add loading="lazy" to below-the-fold images so they don't block the initial load.
• Resize before you convert: there's no point serving a 4000px image into an 800px slot. Do it in one pass with the Image Resizer, then convert.

What to expect

For a typical content or e-commerce page, moving the main images to WebP commonly cuts total image weight by a third or more. That usually shows up directly in your Largest Contentful Paint, because the largest element on the page is so often an image, and LCP is one of the Core Web Vitals Google uses to assess page experience.

Keep your originals

WebP is a delivery format. Keep your original PNGs and JPGs (or a lossless master) as your source of truth, and generate WebP copies from them. If you ever need to hand a file to a tool that doesn't speak WebP, the same converter decodes it back to PNG or JPG in seconds.

If you're weighing WebP against the newer AVIF format, I've written a full comparison of AVIF, WebP and JPEG. Short version: WebP is the safe, universally supported win today.

Sources

• An image format for the Web (Google WebP documentation)
• WebP browser support (caniuse.com)
• �6� element (MDN Web Docs)
• Largest Contentful Paint (web.dev)