Image Compressor Tool - Client-Side Image Compression Resizing and Format Conversion

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Compress, resize, and convert images entirely in your browser. Supports JPEG, PNG, and WebP with an interactive before/after comparison slider. Your images never leave your device — all processing happens locally using the Canvas API with zero server communication.

All processing is performed entirely in your browser using client-side JavaScript and the HTML5 Canvas API. No images are transmitted to any server. Your photos and images never leave your device.

  • This tool is provided "AS IS" without any warranties of any kind.
  • The author accepts no responsibility for any data loss or quality degradation.
  • Canvas-based processing may produce slight color or quality variations compared to native image editors.
  • Always keep backups of your original images before compressing.
  • By using this tool, you accept full responsibility for any outcomes.

This tool uses client-side JavaScript for all processing. No data is transmitted to servers, no files are uploaded online, all processing happens locally in your browser. Once loaded, this tool continues to work even without an internet connection. For more details, please refer to our Web Tools Disclaimer.

Drop images here, click to browse, or paste from clipboard
JPEG, PNG, WebP, BMP, GIF — up to 50 MB per file, 20 files max
Original —
Compressed —
Total Savings —

Batch Settings — Apply to All Images

Features

  • 100% Client-Side Processing: Your images are never uploaded to any server. All compression, resizing, and format conversion happen entirely in your browser using the HTML5 Canvas API.
  • Interactive Before/After Comparison: Drag the slider to visually compare original and compressed images side by side, helping you find the perfect quality-to-size balance.
  • Smart Presets: One-click optimization for common use cases — Web Optimized (WebP), Email Friendly, Social Media, Thumbnail, HD/Full HD/4K, and Print Quality.
  • Multiple Format Support: Convert between JPEG, PNG, and WebP formats. The tool auto-suggests the best output format based on your source image type.
  • High-Quality Downscaling: Uses multi-step progressive downscaling (Lanczos-like) for significantly better quality compared to single-step resize.
  • Batch Processing: Process up to 20 images at once with individual or batch settings. Apply the same preset, format, and quality to all images simultaneously.
  • Per-Image Controls: Fine-tune quality, format, and dimensions individually for each image with real-time savings calculation.
  • Aspect Ratio Lock: Maintain proportions while resizing with a toggleable aspect ratio lock.
  • Clipboard Paste: Paste screenshots directly from your clipboard — no file saving required.
  • Privacy Metadata Stripping: Canvas-based processing automatically removes EXIF metadata (GPS location, camera info) from output images.
  • Offline Capable: Once loaded, the tool works without an internet connection.

How to Use

  1. Drop image files onto the drop zone, click to browse, or paste from clipboard (Ctrl+V / Cmd+V).
  2. For each image, choose a preset or manually adjust the output format, quality slider, and dimensions.
  3. Click "Compress" on an individual image or "Compress All" to process the entire batch.
  4. Use the interactive before/after slider to compare the original and compressed versions.
  5. Review the file size savings shown for each image and in the summary statistics bar.
  6. Click "Download" on individual images or "Download All" to save all processed images.

Important Notes

  • WebP format offers the best compression for photographs. Use it for maximum file size reduction.
  • PNG format is lossless and best for images with transparency, text, or sharp edges (screenshots, logos).
  • JPEG quality between 75-85% typically provides the best balance of quality and file size.
  • The tool will never upscale images beyond their original dimensions to prevent quality loss.
  • Very large images (over 20 megapixels) may take longer to process depending on your device.
  • Canvas-based format conversion automatically strips EXIF metadata from output files, which improves privacy but means GPS data and camera info will not be preserved.
  • AVIF format is not yet supported due to limited browser Canvas API export support.

References:
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Web Tools Collection

Written by Hidekazu Konishi