WebP vs JPEG: when should you switch?
WebP cuts 25-35% off JPEG file size at the same quality and is supported by 97%+ of browsers. This post breaks down when to switch and when to stick with JPEG.
WebP was created by Google in 2010, but it only became truly mainstream in late 2020 when Safari on iOS 14 finally added support. Today 97%+ of browsers support WebP, including every modern version of Edge, Firefox, Chrome, and Safari across all platforms.
So why do people still use JPEG? Short answer: legacy software compatibility, offline editing tools, and habit. This post unpacks when to switch to WebP and when to stick with JPEG.
Why WebP is smaller than JPEG
JPEG uses DCT (Discrete Cosine Transform), a technique from 1992. WebP uses VP8 prediction (same codec family as YouTube's WebM video) plus better entropy coding. Specifically:
- Predictive coding: WebP predicts pixel values from neighboring pixels and only stores the delta. Uniform regions (sky, white walls) cost nearly nothing.
- Smarter block-based chroma subsampling: WebP defaults to YUV420 but slices blocks more cleverly — fewer artifacts at high-contrast edges.
- Lossless + alpha channel: WebP supports both a lossless mode (like PNG but ~26% smaller) and transparency — JPEG has no alpha.
Real-world result: WebP saves 25-35% in file size versus JPEG at the same perceived quality. For images with large uniform regions (UI screenshots, illustrations), savings can hit 50%+.
When you should switch to WebP
For nearly every web use case:
- Website imagery: better page-speed scores, faster LCP, better Core Web Vitals — all of which lift SEO ranking. Google explicitly rewards WebP.
- Email marketing: most modern email clients render WebP. Gmail, Outlook.com, and Apple Mail all support it.
- Mobile app assets: iOS 14+ and Android 4+ decode WebP natively, shrinking your bundle.
- Image-heavy blogs / portfolios: ~30% faster average load, especially on slow connections.
When to stick with JPEG
A few cases where JPEG is still the safer choice:
- Sending files to clients on older editing software: Photoshop CS6 (2012) doesn't open WebP natively. Lightroom Classic before 11.4 doesn't either.
- Print workflows: pro printers using older RIPs may not handle WebP.
- Camera RAW pipelines: if your flow is RAW → JPEG for the client, keep JPEG so the client can open files without friction.
- Internal Explorer < IE11: rare, but if your audience runs old corporate Windows, you need a JPEG fallback.
Bulk converting in seconds
The fastest way to convert a folder of JPEGs to WebP without installing anything:
- Open Image Optimizer in your browser.
- Drag-drop your JPEG folder onto the page.
- In Settings → "Output format" pick WebP.
- Choose the "Medium" preset for a balanced size/quality tradeoff.
- Download the .zip — every file is now .webp.
The app processes 3 images in parallel via RxJS, so a large batch won't freeze your browser. Everything runs client-side — your files never hit a server.
What about AVIF?
AVIF (AV1 Image File Format) is next-gen — about 20% smaller than WebP again. But browser support sits at ~92% (Edge and some older Safari builds still trail). Encoding AVIF is also 5-10× slower than WebP. Recommendation: ship WebP in production for 2026, and re-evaluate AVIF in a year or two.
Bottom line
With 97%+ browser support and 25-35% file-size savings, WebP should be the default for any new web imagery. Keep JPEG only when you need legacy software compatibility. A bulk convert takes seconds in the browser — no reason to delay.