How to Convert Images to WebP Format

WebP cuts file sizes by 25–34% vs JPEG and 26% vs PNG with no visible quality loss. Here's exactly how to convert your images and when to use each output format.

Google's PageSpeed Insights will flag every non-WebP image on your site. Chrome, Firefox, Safari, and Edge all support it. Converting your images to WebP is one of the highest-ROI performance improvements you can make — and with ToollyX's Image Converter, it takes about fifteen seconds per batch.

Why WebP Wins on Size

WebP was developed by Google and released in 2010, derived from the VP8 video codec. It uses a more sophisticated compression algorithm than JPEG or PNG:

  • vs JPEG: 25–34% smaller at equivalent visual quality, because WebP uses predictive coding that accounts for neighbouring blocks more efficiently.
  • vs PNG: 26% smaller for lossless compression; even smaller for lossy with transparency (PNG-24 doesn't support lossy at all).
  • Supports transparency: Unlike JPEG. Unlike PNG-24, it can do it at smaller sizes with lossy encoding.
  • Supports animation: WebP can replace GIF animations at dramatically smaller file sizes.

How to Convert: Batch WebP Conversion on ToollyX

The Image Converter handles multiple files in a single run. Here's the exact workflow:

1
Select WebP as the output format
The four format buttons — JPG, PNG, WebP, BMP — sit at the top. Click WebP before uploading. The tooltip says "Best compression + transparency."
2
Set quality (1–100)
Default is 85. This is the sweet spot — perceptually indistinguishable from 100 but significantly smaller. For hero images where quality is critical, use 90. For thumbnails or icons, 70–75 is fine.
3
Upload your images
Drag multiple files at once into the drop zone. The tool processes all of them simultaneously and shows original vs converted size for each file.
4
Download individually or all
Each converted image has its own Download button. The size comparison shows exactly how much space you saved per file.

Quality Setting: What Number Should You Use?

QualityUse CaseTypical Size vs JPEG
90–100Hero images, print-quality assets−20 to −30%
80–89Blog images, product photos−30 to −40%
70–79Thumbnails, social previews−40 to −50%
60–69Very small file size needed, quality acceptable−50 to −60%
Below 60Not recommended — visible artefacts appear−60%+

PNG to WebP: Preserving Transparency

This is where WebP really shines. A logo with a transparent background as PNG-24 might be 180KB. The same logo as WebP at quality 85 might be 40–60KB — with transparency fully preserved. The Image Converter handles this automatically: when converting a PNG with an alpha channel to WebP, transparency is retained.

Note: Converting to JPG loses transparency (the tool fills white). If transparency matters, convert to WebP or PNG only.

Browser Compatibility in 2026

WebP is supported by 97%+ of browsers globally as of 2026. The only legacy holdout was Internet Explorer, which is effectively dead. If you're still supporting IE (you shouldn't be), you'd need a JPEG fallback via the HTML <picture>element. For everyone else, WebP is safe to deploy as the primary format.

After Converting: Next Steps

  • Resize before deploying — Use the Image Resizer to hit the exact pixel dimensions your CMS or design system needs.
  • Compress further if needed — The Image Compressor applies additional lossy compression on top of the WebP encoding.
  • Crop for aspect ratio — Social platforms have specific aspect ratios. The Image Cropperlets you drag to your exact crop area.
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