Convert Images to WebP for WordPress — Fix the PageSpeed Next-Gen Formats Warning
FreeConvert JPEG and PNG images to WebP to pass Google PageSpeed's 'Serve images in next-gen formats' warning. WordPress 5.8+ accepts WebP natively — no plugin required.
What's next
Settings guide
JPEG vs PNG vs WebP — choosing the right conversion
| Source Format | WebP Conversion | Expected Size Reduction | Notes |
|---|---|---|---|
| JPEG (photos) | Lossy WebP | 25–35% smaller | Best choice for product and editorial photography |
| PNG (graphics) | Lossless WebP | 26% smaller on average | Use for logos, icons, UI elements with transparency |
| PNG (photos) | Lossy WebP | 40–50% smaller | PNG photos are inefficient — WebP dramatically smaller |
| Transparent PNG | Lossless WebP with alpha | 26% smaller | Preserves transparency for UI images |
WordPress version and WebP support
- ·WordPress 5.8+: Native WebP upload support. No plugin required. Upload WebP files directly to Media Library.
- ·WordPress 5.7 and earlier: WebP files may upload but certain image processing operations (thumbnail generation, resizing) can fail without server-side WebP support (GD library or Imagick with WebP enabled). Check with your host before migrating older installations.
Lossy vs lossless WebP by use case
Use lossy WebP (quality 80–85%) for photographs, product images, and editorial content — the size reduction is 25–35% with no visible quality difference at display sizes. Use lossless WebP for logos, icons, illustrations, and images with flat colours or sharp edges — lossless preserves pixel-perfect accuracy while still reducing file size 26% versus PNG.
Format comparison
WebP vs AVIF — should you go further?
AVIF is the next step after WebP — it achieves 50% smaller file sizes than JPEG at equivalent quality. However, AVIF encoding is significantly slower (relevant for server-side conversion) and WordPress's AVIF support via GD/Imagick is less consistent than WebP across hosting providers.
WebP is the pragmatic choice today: universal browser support (Chrome, Firefox, Safari 14+, Edge), reliable WordPress 5.8+ handling, and substantial size reduction over JPEG/PNG. AVIF is worth adopting as a secondary option for manually converted images once your hosting environment reliably supports it.
Google PageSpeed's "Serve images in next-gen formats" warning is satisfied by WebP — you do not need AVIF to pass the check. Switching to WebP removes the red warning and contributes to a significantly improved score.
How it works
Upload your JPEG or PNG
Drop any image file into the converter. Works with single files or batch uploads.
Choose lossy or lossless WebP
Lossy for photos (quality 80–85%). Lossless for logos, icons, or transparent graphics.
Compare file sizes
See the before and after sizes — typical savings are 25–35% for photos and 26% for graphics.
Download and upload to WordPress
Download the WebP file and upload directly to your WordPress Media Library (requires WordPress 5.8+).
About this format
Google PageSpeed Insights flags a "Serve images in next-gen formats" warning when JPEG or PNG images are used where WebP or AVIF could save significant bytes. This warning appears in red and contributes to a lower Performance score — which feeds into Google's Core Web Vitals assessment of your WordPress site. The single most direct fix is converting JPEG and PNG uploads to WebP before uploading them to WordPress.
WordPress 5.8 (released July 2021) added native WebP upload support to the Media Library. If your site is on WordPress 5.8 or later, you can upload WebP files directly — no plugin, no server-side configuration needed. The conversion step happens before upload, in your browser, using this tool.
WebP is typically 25–35% smaller than JPEG and 26% smaller than PNG at equivalent visual quality. On a page with 8 images, switching from JPEG to WebP can reduce total image payload by 200–400KB — often enough to move a PageSpeed score from 60s to 80s+.