Image Compressor
Canvas APIIntelligently compress image file size
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Supports JPG, PNG, WebP, AVIF, BMP and other common formatsFrequently Asked Questions
How It Works
The Image Compressor uses the HTML5 Canvas API with JPEG/WebP quality parameters and optional resolution downscaling to reduce image file sizes. The compression operates through two mechanisms: lossy encoding quality adjustment and pixel count reduction.
Quality-based compression: The Canvas toBlob() method accepts a quality parameter (0.0-1.0) for JPEG and WebP. Lower values apply more aggressive quantization to the DCT (Discrete Cosine Transform) coefficients, reducing file size at the cost of detail. The relationship is non-linear — quality 0.7 typically produces files 50-70% smaller than quality 1.0.
Resolution scaling: The optional max width/height parameter triggers proportional downscaling using Canvas drawImage's scaling capabilities. Reducing a 4000×3000 image to 1920×1080 removes 77% of pixels, dramatically reducing file size while maintaining visual quality on most displays.
Tips & Best Practices
- Quality 70-85% is the sweet spot for web images — provides 50-70% size reduction with imperceptible quality loss at normal viewing distances.
- Resolution matters most: Reducing from 4000px to 1920px width has far more impact on file size than quality adjustment.
- WebP at 80% produces smaller files than JPEG at 95% with similar visual quality — always prefer WebP.
- Check for banding: Aggressive compression can cause color banding in gradients. Zoom in to verify smooth transitions.
- Target specific dimensions: If you know the display size, resize to match — a 1920px image displayed at 800px wastes bandwidth.
- Before/after comparison: Download both versions and compare side by side to ensure quality is acceptable for your use case.
Use Cases
Website managers compressing hero images and product photos to improve page load speed and Core Web Vitals performance scores.
E-commerce platforms reducing product image file sizes to decrease page weight and improve mobile shopping experience. Email marketers compressing images to stay under email client size limits and ensure fast loading. Bloggers optimizing featured images for faster page loads without sacrificing visual quality. Mobile app developers compressing image assets to reduce app download size. Social media managers optimizing images for platforms that apply their own compression — better to control the process yourself.