Free browser-based image compressor, resizer, and format converter — JPEG, PNG, WebP, and AVIF with no upload needed.
Krzen is a free client-side image compressor that processes images entirely in your browser using the Canvas API. Compress JPEG, PNG, and WebP images with adjustable quality, resize to custom dimensions, convert between formats including AVIF, and compare before/after with a visual slider. Your images never leave your device — perfect for sensitive screenshots, client work, and privacy-first workflows.
- Adjustable quality slider from 1-100 with real-time file-size preview
- Output format selection: JPEG, WebP, PNG, and AVIF
- Custom width and height resizing with aspect ratio preservation
- Visual before/after comparison with draggable slider
- Bulk compression for processing multiple files simultaneously
- Page load impact calculator showing time savings across connection types
- Drag-and-drop upload supporting any image format the browser can decode
- EXIF metadata stripping for privacy
- 100% client-side — no data leaves your browser
- MIT licensed
- No signup, no tracking
- Pure HTML, CSS, and vanilla JavaScript
- No build step
- No external dependencies (except Google Fonts on some pages)
- Hosted on GitHub Pages with Cloudflare CDN
Krzen is part of Zovo Tools — free developer tools by a solo developer. No tracking, no signup, no nonsense.
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MIT licensed.
Built and maintained by Michael Lip. For questions or feedback: support@zovo.one