How to Convert PNG or JPG to WebP for a Faster Website
Heavy PNG and JPG images are slowing down your site. Convert them to WebP in your browser, keep the quality, and cut page weight in minutes.
Run any slow website through a performance checker and you’ll almost always find the same culprit near the top of the report: images. Not scripts, not fonts — plain old PNG and JPG files, sitting on the page at two or three times the file size they need to be. If you’re building a site, a landing page, or even just a blog, converting those images to WebP is one of the few performance fixes that takes minutes and actually moves the needle.
Why WebP matters for page speed
WebP is a modern image format built specifically to be smaller than PNG and JPG without a visible drop in quality. On photos, it typically shaves 25-35% off the file size compared to a similarly-compressed JPG. On screenshots, logos, and graphics with flat colors or transparency, the savings against PNG can be even bigger, often 50% or more, because WebP compresses that kind of image far more efficiently.
That difference adds up fast. A blog post with a dozen screenshots, an e-commerce page with product photos, a portfolio full of images — each one loading a third smaller means a faster First Contentful Paint, a better Largest Contentful Paint score, and a page that feels instant instead of sluggish on a mobile connection. Search engines factor page speed into ranking too, so this isn’t just about the visitor’s experience.
The catch with PNG and JPG is that they were designed decades ago, long before anyone worried about mobile data caps or Core Web Vitals. They do the job, but they carry more bytes than modern compression needs to store the same picture. WebP was made to fix exactly that gap, and virtually every current browser supports it now, so there’s no real reason to keep shipping the heavier files.
Converting your images to WebP
- Gather the images you want to convert. Screenshots, product photos, hero banners — anything currently sitting on your site as
.pngor.jpg. - Open the image converter and drop your files in. It handles batches, so you can convert an entire folder of images in one pass instead of doing them one by one.
- Choose WebP as the output format. For photographs, a quality setting around 75-85% usually looks identical to the original while cutting the file size substantially. For graphics with sharp edges or transparency, WebP’s lossless mode keeps every pixel exact.
- Download the converted files and swap them into your site, replacing the old PNG or JPG versions in your image folder or CMS media library.
- Check the result. Open the new files at full size and compare them side by side with the originals. If anything looks off on a particular image, you can always re-convert that one at a slightly higher quality setting.
If your site needs to support older browsers or software that doesn’t recognize WebP yet, keep the original PNG or JPG as a fallback and serve WebP to everyone else — most modern content management systems and web servers can do this automatically with an <picture> tag or content negotiation.
A quick note on quality
WebP isn’t magic — it’s still compression, and pushing the quality slider too low will introduce the same blocky artifacts you’d get from over-compressing a JPG. The sweet spot for most website images sits comfortably above 70% quality, where the file is already dramatically smaller than the PNG or JPG original but the visual difference is impossible to spot at normal viewing sizes. Only drop lower if you’re chasing every last kilobyte on a genuinely bandwidth-constrained page.
It’s also worth remembering that WebP is a raster format like PNG and JPG, made of pixels rather than mathematical shapes. That makes it a great fit for photos and screenshots, but for things like logos or icons that need to scale to any size without blurring, an SVG is still the better tool for the job.
Your images never leave your browser
Every conversion in this guide happens locally, right inside your browser tab. The images you drop in are never uploaded to a server, stored anywhere, or seen by anyone else — they’re processed on your own device and the converted files come straight back to you. That matters if you’re handling client screenshots, product mockups under NDA, or simply prefer not to hand your files over to a third-party server just to change their extension.
Converting a batch of images to WebP is a small change, but it’s the kind of small change that compounds. Faster pages keep visitors around longer, rank a little better, and cost less to serve — all for the price of a few minutes swapping file formats before your next deploy.