Yes, use WebP. In 2026 that is the whole answer for images on a website you control: every browser has rendered WebP for years, the files run 25–35% smaller than the JPG or PNG they replace, and nothing about your visitors' experience changes except pages loading faster. The interesting questions are the operational ones: which images are worth converting, how to serve WebP without breaking anything, and where PNG and JPG still belong. That is what this guide covers.
What converts well, and what to leave alone
Not every image deserves the effort. The decision tree is short:
Convert the big stuff first. Hero images, product photos, article illustrations — anything measured in hundreds of kilobytes. A 450 KB JPG becoming a 300 KB WebP is a real win, multiplied by every visitor on every page load. Product grids and galleries are where the compounding happens.
Convert PNG graphics that carry weight. Screenshots, diagrams, and transparent UI images that went up as PNG shrink dramatically as lossy WebP, and even lossless WebP beats PNG by about a quarter. The technical why is in WebP vs PNG.
Leave the tiny files alone. A 4 KB icon is a rounding error. Converting it saves nothing perceptible and costs you a step in the pipeline. The rule: if the file is already small enough that you never thought about it, keep not thinking about it.
The migration path
- Inventory the images on the pages that matter — homepage, top landing pages, product templates. Analytics knows which those are.
- Batch-convert the PNG and JPG assets. Drop the folders into PNG to WebP or JPG to WebP; both run locally in your browser, handle whole folders, and hand back a ZIP. Nothing leaves your machine, which matters when the assets are client work.
- Keep the originals. WebP is lossy in its common mode. Your PNG/JPG masters stay the source of truth for any future re-encode.
- Swap the references in templates and re-upload. Filenames are preserved by the converter except for the extension, so a find-and-replace on
.png→.webpin your templates covers most of it.
If your site runs on a CMS
Check before converting anything by hand. Modern WordPress accepts WebP uploads and generates sub-sizes like any other image, and many managed hosts and CDNs can convert to WebP automatically at the edge — in that case the migration is a settings page, not a file operation. Manual conversion is still the right path for static sites, hand-built templates, and any CMS whose media pipeline predates the format.
Serving with a fallback
The <picture> element lets modern browsers take WebP while anything ancient falls through to the original:
<picture>
<source type="image/webp" srcset="/img/hero.webp" />
<img src="/img/hero.jpg" alt="Hero image" width="1600" height="900" />
</picture>
Browsers pick the first source they understand; everything else reads the <img> as if nothing happened. In 2026 this is belt-and-suspenders — browser WebP support has been universal for years — but it costs one line and removes the question entirely. The alternative, server-side content negotiation via the Accept header, serves the same result at the URL level; it is powerful but moves the complexity into server config, which is a trade most small sites should decline.
What to keep as PNG or JPG
Three categories stay in the old formats even on a fully WebP site:
Files visitors download. A "download press kit" link should hand out PNG or JPG, because the person receiving it might open it in anything. The support gap outside browsers is real — the same one we mapped in WebP vs JPG.
Open Graph and email images. og:image and newsletter assets get fetched by crawlers, chat apps, and mail clients with much older image stacks than browsers. Serve those as JPG or PNG or accept that some previews silently fail.
Your master files. Always. WebP is the shipping container, not the archive.
For the broader landscape of where each format sits, the web image formats guide has the full map.
After the switch
Run your top pages through a speed test before and after. The improvement shows up exactly where it should: largest contentful paint, total page weight, and the mobile experience where the bytes hurt most. If a page barely moves, its images were already small — which means the decision tree above did its job and told you to skip them. Save the before-and-after numbers; they are the argument for migrating the rest of the site.
The conversion itself is the fast part of this project. A folder of product photos through PNG to WebP takes under a minute; the template edits take longer. Start with your heaviest page, and let the waterfall chart argue with anyone who still thinks this is optional.