Image Compressor

How Image Compression Works

This tool uses the browser's built-in Canvas API to redraw your image at the specified quality level. JPEG compression works by dividing the image into 8×8 pixel blocks and applying Discrete Cosine Transform (DCT) to encode colour and luminance information. Lower quality settings discard more high-frequency detail (fine textures and edges), resulting in smaller files with some visual loss. PNG compression is lossless — reducing PNG quality in this tool works by resizing the image rather than degrading quality.

Choosing the Right Format

JPEG: Best for photographs and images with gradual colour transitions. JPEG at 70–80% quality is visually indistinguishable from the original for most purposes and is typically 40–70% smaller than the original file. PNG: Best for screenshots, logos, images with text, and images requiring transparency. PNG is always lossless but produces larger files than JPEG for photographs. WebP: Google's modern format that offers 25–35% better compression than JPEG at the same visual quality. Supported by all modern browsers but may not work in older software.

Recommended Quality Settings by Use Case