WebP vs JPEG: Which Image Format Should You Use in 2026?

Choosing the wrong image format is one of the easiest performance mistakes to make on a website. JPEG has dominated the web for thirty years. WebP has been available in every major browser since 2020. Yet most websites still serve JPEG by default.

This guide cuts through the confusion. By the end you will know exactly when to use WebP, when JPEG still makes sense, and how to convert everything you already have in about thirty seconds.

What is JPEG?

JPEG (Joint Photographic Experts Group) was standardised in 1992. It uses lossy DCT (discrete cosine transform) compression, which discards colour detail the human eye is less sensitive to — particularly in high-frequency areas like fine texture and foliage.

JPEG has one job: compress photographs. It does it well. A quality-80 JPEG is usually indistinguishable from the original at normal viewing sizes, and the file will be roughly 10–20× smaller than an uncompressed TIFF.

What JPEG cannot do: transparency. If your image has an alpha channel, JPEG simply drops it and fills the background with white.

What is WebP?

WebP was developed by Google and released in 2010. It was built on the VP8 video codec and later extended in WebP 2 with improved lossless and transparency modes. Google's stated goal was a format that outperformed JPEG, PNG, and GIF simultaneously.

WebP supports:

• Lossy compression (better than JPEG at equivalent quality)
• Lossless compression (20–30% smaller than PNG on average)
• Transparency (alpha channel, like PNG)
• Animation (like GIF, but far smaller)

A single format that replaces three. That is the pitch.

File size: how much smaller is WebP?

This is the question everyone wants answered with a number. The honest answer is: it depends on the image. But here are the consistent findings across independent studies and Google's own benchmarks:

For a typical product photography page with twelve images averaging 150 KB each as JPEG, switching to WebP saves roughly 500 KB per page load. At scale, that is significant bandwidth and a measurable improvement in Core Web Vitals — specifically Largest Contentful Paint (LCP).

Visual quality: is there a difference?

At equivalent file sizes, WebP produces better visual quality than JPEG. The artifacts are different in character: JPEG shows classic "blocking" in flat areas and ringing around high-contrast edges. WebP artifacts, when visible, tend to appear as a slight softening rather than geometric distortion.

At equivalent quality settings, WebP files are simply smaller. You are not trading quality for size; you are getting both.

The one area where JPEG can still hold its own: very high-quality settings (90+), where the gap between formats narrows and both produce output that looks identical on screen.

Browser support in 2026

WebP is universally supported. There is no longer a meaningful compatibility reason to prefer JPEG.

If you need to support Internet Explorer 11 (usage below 0.3% globally as of 2026), you would need a JPEG fallback. For every other target, WebP is safe.

When does JPEG still make sense?

WebP wins on almost every technical metric, but there are real-world situations where JPEG remains the pragmatic choice.

Photography exports and original files. Keep your originals as lossless files (TIFF, PNG, RAW). Export a JPEG as an intermediate if your image editing toolchain does not yet support WebP natively. Then convert to WebP for deployment.

Email. Most email clients — particularly Outlook and Apple Mail on older iOS — do not render WebP inline. For images embedded in email, JPEG is still the safe default.

Third-party platforms. If you are uploading to a platform that re-processes images (Instagram, Shopify, some CMSs), the platform will compress your image again regardless of format. In those cases upload the highest-quality JPEG you have and let the platform handle it.

Compatibility with older editing software. If your team edits images in software that cannot open WebP, keep working in JPEG internally and convert to WebP only at the deployment step.

When should you use WebP?

Use WebP for everything you serve directly on a website or web app:

• Product photography
• Blog post hero images and inline images
• Background images
• UI illustrations
• Icons and logos (especially if transparency is needed)
• Animated content (replace GIF entirely)

The conversion step is the only friction. Once you have a workflow that outputs WebP automatically — whether that is a build tool, a CDN transform, or a browser-side tool like img.lu — there is no reason to serve JPEG on the web.

SEO and Core Web Vitals

Google's PageSpeed Insights explicitly recommends serving images in "next-gen formats" — WebP and AVIF. It flags JPEG and PNG as opportunities for improvement and estimates the potential savings in kilobytes.

The performance benefit feeds directly into:

• LCP (Largest Contentful Paint): smaller images load faster, and the LCP element is almost always an image
• Total Blocking Time: reduced network time means less contention with render-critical resources
• Bandwidth costs: users on mobile data connections benefit directly

Switching a JPEG-heavy page to WebP routinely improves LCP by 200–500 ms, which can move a site from "needs improvement" to "good" in a single deploy.

What about AVIF?

AVIF is the next generation after WebP, based on the AV1 codec. It achieves roughly 20% smaller files than WebP at equivalent quality. If WebP beats JPEG by 30%, AVIF beats JPEG by around 50%.

The trade-off is encoding speed. AVIF is significantly slower to generate than WebP — a consideration if you are converting large batches in real time. Browser support is also slightly narrower (Safari added support in Safari 16, released 2022).

The practical recommendation for 2026: use WebP as your primary format. It has universal support, excellent tooling, and delivers dramatic savings over JPEG. Adopt AVIF for your most critical above-the-fold images where you have time to pre-encode them.

How to convert JPEG to WebP

The easiest way: drag your images into img.lu. It runs entirely in your browser, converts to WebP in seconds, and gives you a download with the exact quality level you choose. Nothing is uploaded to any server.

If you need batch conversion in a build pipeline:

# Using cwebp (Google's official CLI)
cwebp -q 80 input.jpg -o output.webp

# Using ImageMagick
convert input.jpg -quality 80 output.webp

# Using ffmpeg (fast, handles bulk well)
ffmpeg -i input.jpg -quality 80 output.webp

For Node.js projects, sharp is the standard:

import sharp from 'sharp';

await sharp('input.jpg')
  .webp({ quality: 80 })
  .toFile('output.webp');

The verdict

Use WebP for everything you serve on the web. Keep JPEG for email, legacy toolchains, and third-party platform uploads. Convert your existing assets — the quality is identical and the savings are immediate.

Start with img.lu. Drop in a JPEG, get a WebP, see the difference for yourself.