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ConvertBox

Compress Image

Reduce image file size instantly in your browser. Optimize PNG, JPG, WebP, and HEIC files locally without quality loss. Free, secure, and no uploads.

Max CompressionBest Quality
🗜️

Select Images

You can select multiple images at once

Max file size: 50MB • Multiple files allowed

or drag and drop · press Enter to browse

Smart Compression

Minimize size while keeping quality

Secure Processing

Files are never sent to a server

Batch Processing

Compress multiple files at once

How to Use

  1. Upload your image (JPG, PNG, WebP, or HEIC format — up to 50MB per file).
  2. Adjust the compression slider to find your desired balance between image quality and file size savings.
  3. Click 'Compress Image' — processing runs entirely locally inside your browser via Canvas API.
  4. Review the original vs compressed file sizes and download your optimized image.
  5. Convert HEIC photos from iPhones into standard WebP or JPG formats for easy sharing.
  6. All calculations happen client-side, ensuring your photos never leave your device.

All processing is done in your browser, and files are never sent to a server.

Frequently Asked Questions

Our tool uses advanced client-side algorithms to selectively discard less visible image details, resulting in significant file size savings with virtually no visible difference in quality.
We support JPEG, PNG, WebP, and HEIC formats. Output formats include JPEG, PNG, and WebP.
Yes. When you compress an iPhone HEIC file, it can be exported as a standard JPG or WebP, making it compatible with all platforms.
No. The entire compression process occurs within your browser using HTML5 Canvas. Your photos are never sent over the network.
Currently, we process one image at a time to prevent browser memory leaks. You can quickly reset and upload the next image.
Yes, by default, our canvas-based compression strips metadata for privacy. This prevents tracking details from leaking online.
We support images up to 50MB. Very large pixel resolutions might be limited by your browser's maximum canvas size.
No. All operations are processed entirely inside your browser's local sandbox using client-side APIs (like WebAssembly, pdf-lib, or HTML5 Canvas). Your files and data never leave your device.
No. All tools on ConvertBox are 100% free. We do not insert watermarks, limit features, or require any registration or payment.
Yes. Once the page and its local library dependencies are loaded in your browser, the conversion logic runs completely offline without needing an active internet connection.

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