How to Convert Images to WebP in WordPress (Step-by-Step)

If you’ve been trying to speed up your WordPress site, you’ve probably come across one recurring recommendation: convert your images to WebP. It’s one of the most impactful changes you can make for page load times, and it doesn’t require a developer or any complex technical work. This guide walks you through exactly how to do it — from understanding what WebP actually is, to choosing the right tool and getting it live on your site.

What Is WebP and Why Should You Care?

WebP is an image format developed by Google, designed specifically for the web. It produces smaller file sizes than JPEG and PNG without a visible drop in quality — in most cases, WebP images are around 25–35% smaller than their JPEG equivalents and up to 80% smaller than PNG files of the same image.

That size reduction matters because images typically account for the largest portion of a web page’s total file size. When images load faster, your entire page loads faster — and Google’s Core Web Vitals score, which directly influences search rankings, rewards that.

Browser support for WebP is now essentially universal. Chrome, Firefox, Safari (since version 14), Edge, and Opera all support it. So there’s very little reason not to use it.

How WebP Affects WordPress Performance

WordPress sites that are image-heavy — think WooCommerce stores, photography portfolios, or news sites — benefit enormously from switching to WebP. A page that previously loaded 20 product images at 150KB each is suddenly loading those same images at 90–100KB each. That’s a saving of over 1MB on a single page, sometimes more.

Google’s PageSpeed Insights and Lighthouse tools have flagged "serve images in next-gen formats" as a recommendation for years. If you’ve seen that warning in your site audit and ignored it, this article is your answer.

Beyond rankings, there’s a real user experience argument here too. Studies consistently show that a one-second delay in page load time can reduce conversions by up to 7%. For an e-commerce site doing even modest revenue, that’s meaningful money left on the table.

Before You Start: A Few Things to Check

Before converting images to WebP in WordPress, it’s worth doing a quick inventory.

Take a backup. Always back up your site before making bulk changes to media files. Most good hosts offer one-click backups, or you can use a plugin like UpdraftPlus.

Check your hosting environment. Most modern hosting providers (Kinsta, WP Engine, SiteGround, Cloudways) support WebP natively. Some budget shared hosts may not — if you’re unsure, ask your host or check their documentation.

Decide on your approach. You can convert images automatically on upload, bulk convert existing images, or use a CDN/caching layer to serve WebP versions dynamically. Most plugins handle all three.

The Easiest Method: Using a WordPress Plugin

For the vast majority of WordPress users, a plugin is the right solution. You don’t need to touch the command line or manually convert files. Here are the most reliable options.

Option 1: Imagify

Imagify is one of the most widely used image optimisation plugins for WordPress, and it handles WebP conversion cleanly. Here’s how to get it set up:

Go to Plugins > Add New in your WordPress dashboard.

Search for "Imagify" and click Install Now, then Activate.

Create a free account at imagify.io to get your API key.

Enter the API key in Settings > Imagify.

Under the WebP format section, enable the option to Create WebP versions of images.

Choose whether to use <picture> tags or .htaccess rewrite rules to serve WebP (the plugin recommends the .htaccess method for most setups).

Click Save Settings.

To convert your existing images, go to Media > Bulk Optimization and run the process. Depending on how many images you have, this could take anywhere from a few minutes to an hour.

Imagify’s free tier allows up to 20MB of image optimisation per month, which is enough for small sites. Paid plans start at around €4.99/month.

Option 2: ShortPixel

ShortPixel is another strong choice, particularly popular among developers and agencies managing multiple sites. The setup process is nearly identical to Imagify — install, enter API key, enable WebP — but ShortPixel also offers a one-time credit purchase option rather than a subscription, which suits sites that don’t upload images frequently.

ShortPixel’s free plan covers 100 images per month, making it a good starting point for smaller blogs or portfolios.

Option 3: Smush (by WPMU DEV)

Smush is probably the most widely installed image plugin in the WordPress repository, partly because it offers a free tier with no API key required. The free version compresses images but does not include WebP conversion — that’s gated behind Smush Pro (part of the WPMU DEV subscription at around $7.50/month).

If you’re already using WPMU DEV for other plugins, Smush Pro makes sense. If not, Imagify or ShortPixel offer better value for WebP specifically.

Converting Images to WebP Without a Plugin

If you’d rather not rely on a plugin — or if you’re managing a high-volume site where plugin-based processing is too slow — there are alternative approaches.

Using Cloudflare Polish

If your site sits behind Cloudflare (which is free to set up), you can enable a feature called Polish in the Speed settings. This automatically converts images to WebP for supported browsers at the CDN level, without touching your original files at all.

It’s worth noting that Cloudflare Polish requires a paid plan (Pro, starting at $20/month). But if you’re already on Cloudflare Pro for other reasons, this is by far the most seamless approach — zero plugins, zero bulk processing, no risk to your media library.

Using WP-CLI for Bulk Conversion

For developers comfortable with the command line, WP-CLI combined with a tool like cwebp (Google’s official WebP encoder) allows bulk conversion directly on the server. This is faster and more controllable than plugin-based processing, but it does require SSH access and some comfort with terminal commands.

This approach is most relevant for agencies managing enterprise-level WordPress installations or headless setups where standard plugin workflows aren’t practical.

Serving WebP Images Correctly in WordPress

Converting images is only half the job — you also need to make sure WordPress is actually serving the WebP versions to visitors.

Most plugins handle this automatically through one of two methods:

<picture> tag method: The plugin rewrites your image HTML so the browser sees both the WebP and the original format. Browsers that support WebP download the WebP; others fall back to the JPEG or PNG.

.htaccess rewrite method: The server checks whether the browser accepts WebP (via the Accept header), and if it does, silently serves the .webp file instead of the original. This is transparent — the image URL in the HTML doesn’t change.

Both methods work well. The .htaccess approach is slightly more efficient and doesn’t require any changes to your HTML, but it does require that your server supports mod_rewrite (most Apache-based hosts do). If you’re on Nginx, you’ll need a similar rewrite rule in your server config.

Checking That WebP Is Working

Once you’ve set everything up, it’s important to verify that WebP images are actually being delivered.

The quickest way: open your site in Chrome, right-click any image, and select Inspect. In the Network tab, reload the page, filter by "Img", and click on an image request. Under the Response Headers, look for the Content-Type field — if it says image/webp, you’re good to go.

You can also use Google PageSpeed Insights (pagespeed.web.dev) to re-run your site audit. If WebP is serving correctly, the "serve images in next-gen formats" warning should disappear or show a significantly reduced impact.

Another useful tool is WebPageTest (webpagetest.org), which provides a waterfall chart of all resources loaded on your page. You can see the before/after impact of WebP on total image payload weight.

Frequently Asked Questions

What is the difference between WebP and JPEG?
WebP is a newer format designed for the web, typically producing files 25–35% smaller than JPEG at comparable quality. JPEG has been the standard for photos online for decades, but WebP offers better compression without the visual degradation that comes with heavily compressed JPEGs. For most web use cases, WebP is the better choice today.

Will converting to WebP break my existing images?
No — reputable plugins keep your original images intact and create separate WebP versions alongside them. If a browser doesn’t support WebP (which is rare now), it will be served the original file automatically. There’s no risk to your existing media library as long as you’ve taken a backup first.

Is it worth converting old images on an established site?
Absolutely. In many cases, bulk-converting existing images delivers the biggest performance gain of any single optimisation step. A site with hundreds of product images or blog post thumbnails can shed several megabytes of page weight in one afternoon, which translates directly to faster load times and potentially better rankings.

Do WebP images affect SEO?
Positively. Google’s Core Web Vitals — particularly Largest Contentful Paint (LCP) — are influenced by how quickly your main images load. Smaller image files load faster, which improves LCP scores. Google has been using Core Web Vitals as a ranking factor since 2021, so this has a measurable effect on SEO performance.

Can I use WebP with page builders like Elementor or Divi?
Yes. WebP images work normally within any page builder that uses WordPress’s standard media library. The builder doesn’t need to know anything about the format — it just references the image file, and your plugin or server configuration handles serving the WebP version to supported browsers.

Conclusion

Converting images to WebP in WordPress is one of those tasks that looks technical on the surface but is genuinely straightforward once you understand the steps. The tools are readily available, most are free or low-cost, and the performance gains are real and measurable.

The practical starting point for most site owners is to install Imagify or ShortPixel, enable WebP conversion, run a bulk optimisation on existing images, and verify the results in PageSpeed Insights. That’s it. For more complex setups — high-traffic stores, multisite installations, or sites already on Cloudflare — the other approaches covered here give you more flexibility and control.

Faster images mean a faster site, and a faster site means better user experience, better rankings, and better results. It’s one of the highest-impact changes you can make with relatively minimal effort.

Ready to get started or want some advice on the best approach for your site? Get in touch with our team — email us at moc.ssobebolgobfsctd-86b21f@ofni or call +353 1 868 2345 and we’ll be happy to walk you through your options, whether you’re looking to optimise an existing site or build something new with performance baked in from the start.

← Back to Blog

Dublin's ROI-Driven Digital Marketing Agency Home