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ImageZap

Compress WebP

Being WebP doesn't mean an image is optimized. Re-compress it with sensible settings and scale it to the size you actually need.

Drop your images here

or paste with Ctrl+V · JPG, PNG, WebP, AVIF, JXL, GIF, HEIC · up to 30 MB each

Images are processed on your device and stored only in this browser so you can convert them again.

A WebP can still be too heavy

Converting to WebP is a great first step, but many WebP files out there aren't well optimized:

  • They were exported at quality 90-100 "just in case", when 75-80 looks the same.
  • They have huge resolutions (4000 px wide to be displayed at 800 px).
  • A plugin or CMS generated them with generic settings, or they were saved losslessly despite being photos, which multiplies their size.

ImageZap re-encodes them with libwebp, Google's official encoder, using the settings you choose, and shows you the exact saving for each file.

How to compress WebP

  1. Drag your .webp files or an entire folder.
  2. The output format is Original, so each file stays WebP. Adjust the quality:
    • 75-80: recommended for photos on the web. Practically invisible difference and big savings.
    • 60-70: thumbnails, backgrounds and images displayed small.
    • Lossless: only for graphics, logos or screenshots with flat colors.
  3. If the image is larger than the space it's shown in, turn on Resize (for example, a maximum width of 1600 px).
  4. Click Convert, check the result in the before/after viewer and download.

Compressing something already compressed

There's one detail to keep in mind: a lossy WebP has already discarded information. When you re-compress it, the encoder works on that image, not on the original. That has two practical consequences:

  • Don't raise the quality above what the file had: the result will be bigger and won't recover detail.
  • Avoid re-compressing the same file many times. Each cycle adds a little loss (generation loss). Ideally always start from the original (camera or design JPG or PNG) when you have it.

If a file comes out larger after processing, it was already well optimized: keep the original. ImageZap shows the percentage change for every image precisely so you can spot this.

The advanced options that matter

  • Resizing usually saves more than any quality setting. A 3000 px image shown at 1000 px has 9 times more pixels than needed.
  • Responsive variants: generate several widths (640, 1280, 1920…) at once to use with srcset, so each device downloads only what it needs. More in the guide on responsive images with srcset and sizes.
  • Try AVIF: add AVIF as a second format and compare. For photos it's usually 20-30% smaller than WebP at equal quality.

WebP and Core Web Vitals

Images are the LCP (Largest Contentful Paint) element on most pages. Cutting the weight of the main image is one of the most direct ways to improve that metric and, with it, user experience and rankings. The image checklist for Core Web Vitals sums up the remaining steps: explicit dimensions, fetchpriority, lazy loading and formats.

Frequently asked questions

How much can I shrink a WebP?

It depends on how it was created. A WebP exported at quality 95 at full size can drop 50-80% with quality 78 and a reasonable resize. One that's already optimized will barely change.

Will I notice the difference?

At quality 75-80 it's very hard to see at normal size. Use the comparison viewer to check areas with fine detail or text before downloading.

Is transparency kept?

Yes. WebP supports a full alpha channel and it's preserved when re-compressing.

Are my images uploaded?

No. Everything is processed in your browser using WebAssembly.

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