Image Compressor

Image compression reduces the file size of an image by discarding or encoding pixel data more efficiently. There are two fundamental approaches: lossless compression (ZIP, PNG) preserves every pixel exactly but achieves moderate size reduction; lossy compression (JPEG, WebP) discards imperceptible detail to achieve dramatically smaller file sizes, with the quality/size tradeoff controlled by a quality parameter. For typical photographic content, lossy compression at quality 75–85% is visually indistinguishable from the original at normal viewing distances while reducing file size by 60–80%.

Web performance depends heavily on image file sizes. Images typically account for 60–70% of total page weight on content-heavy websites. Google's Core Web Vitals measure Largest Contentful Paint (LCP) — how quickly the main image on a page becomes visible — and image compression directly impacts this metric. A 4MB hero image loading over a mobile connection causes a poor LCP score and high bounce rates; the same image compressed to 200KB loads in under a second.

This tool compresses images in the browser using the Canvas API's toBlob() method with quality control. The uploaded image is drawn onto an offscreen canvas and exported as JPEG or WebP at the selected quality level. Before-and-after file sizes are displayed so users can judge the compression ratio. All processing is local — images never leave the device. JPEG compression is universally compatible; WebP achieves 25–34% better compression than JPEG at the same quality level and is supported by all major browsers.