Image Compressor & WebP Converter Tool Online
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Compress JPG and PNG files, convert images to WebP, and resize oversized assets before upload. This private browser tool helps improve Core Web Vitals without sending images to a server.
Drop JPG or PNG images here or choose one or more files from your device
Privacy note: nothing is uploaded. Canvas compression happens locally.
How the Image Compressor Works
This online image compressor uses native browser features to optimize files before they reach your CMS, Astro project, or media library.
- Add images, drag and drop JPG or PNG files or select multiple images from your device.
- Choose output settings, select WebP, JPEG, or AVIF when supported, then adjust quality and optional max width.
- Process with canvas, each image is decoded, drawn to canvas, resized if needed, and re-encoded with canvas.toBlob.
- Compare savings, review original size, compressed size, percent saved, dimensions, and a preview.
- Download optimized files, save the compressed images and use them in your website workflow.
Why Image Compression Matters for Core Web Vitals
Images are often the largest assets on a business website. Reducing image weight can improve loading speed, user experience, crawl efficiency, and conversion rate.
- Faster LCP, optimized hero and content images can reduce the time needed to render the largest visible element.
- Lower bandwidth, smaller files help mobile visitors and reduce hosting transfer costs.
- Better SEO foundations, fast pages give search engines and AI crawlers cleaner access to content.
- Better publishing workflow, compressing before upload prevents massive original files from slowing the site later.
For a full performance workflow, pair this compressor with our Image SEO Checker and Core Web Vitals guide.
Image Format Reference
Choose the format based on the image type, required browser support, and publishing workflow.
| Format | Best use | Browser support note |
|---|---|---|
| WebP | Most website photos, product images, and blog graphics | Broad modern browser support and strong compression. |
| JPEG | Maximum compatibility for photos without transparency | Universal support, but larger than WebP at similar quality. |
| PNG | Logos, UI assets, screenshots, and transparent graphics | Lossless and widely supported, but can be large for photos. |
| AVIF | Modern high-compression image delivery | Excellent compression, but canvas export support varies by browser. |
Compression Best Practices
- Resize huge camera photos before adding them to the website.
- Use WebP for content images and keep PNG for logos or graphics that need crisp transparency.
- Keep width and height attributes in HTML to prevent layout shift.
- Use descriptive filenames and alt text after compression so image SEO is not lost.
- For Astro projects, store content images in
src/assets/and use the Astro Image component for final build optimization.
Next steps
Image Compressor related tools and articles
Continue with the closest follow-up checks and guides based on this tool's topic, crawl intent, and optimization workflow.
Image Compressor: FAQ
What does this image compressor do?
It compresses JPG and PNG images in your browser by drawing them to canvas, optionally resizing them, and exporting smaller files as WebP, JPEG, or AVIF when the browser supports AVIF canvas export.
Are my images uploaded to a server?
No. This is a client-side image compressor. Files stay in your browser and are processed locally with canvas and canvas.toBlob.
Which format should I choose?
Choose WebP for most website images because it has broad support and strong compression. Choose JPEG when you need maximum compatibility. Choose AVIF only when your browser supports exporting it and you want very small files for modern browsers.
Can I compress multiple images at once?
Yes. Drag and drop multiple JPG or PNG images, or select multiple files from the upload input. The tool processes each image and creates individual download links.
Does the quality slider affect file size?
Yes. Lower quality usually creates smaller files but may add visible artifacts. For website photos, a quality between 0.7 and 0.85 often gives a good balance between size and visual quality.
What does max width resize do?
Max width limits oversized images before compression. If an uploaded image is wider than the value you enter, it is scaled down proportionally. This can save much more file size than compression alone.
Will PNG transparency be preserved?
Transparency is preserved when exporting to WebP or AVIF in browsers that support it. If you export transparent images as JPEG, the transparent areas are filled with white because JPEG does not support alpha transparency.
Is WebP safe for SEO?
Yes. WebP is supported by modern browsers and helps reduce page weight, improve Core Web Vitals, and speed up image-heavy pages. Always keep descriptive alt text and useful filenames.
How much can this reduce image size?
Savings depend on the original image, dimensions, format, and quality setting. Large unoptimized photos often shrink by 50% to 90% when resized and converted to WebP.
Need Faster Website Images?
We optimize Astro websites for speed, search visibility, and stronger Core Web Vitals with modern image workflows.