Free Image Compressor

No — absolutely not. All image processing happens locally inside your browser using JavaScript and the HTML5 Canvas API. Your images never leave your device and are never stored anywhere. This makes the tool completely private and also works offline once the page is loaded.

For website images, 70–80% quality gives the best balance — usually 40–70% smaller files with no visible difference at normal viewing sizes. For photos you want to print or zoom into, stay at 85–90%. The default of 75% is ideal for most web use cases.

JPG (JPEG) uses lossy compression — great for photographs. PNG uses lossless compression — no quality loss, but larger files, best for logos and graphics with transparency. WebP is Google's modern format that supports both lossy and lossless compression and is typically 25–35% smaller than JPEG or PNG at equivalent quality. Most modern browsers support WebP.

PNG files already use lossless compression, so the Canvas API can't always reduce them further — especially simple graphics or screenshots. Converting a PNG to JPG or WebP format (using the Output Format dropdown) will give a much larger reduction. Also, if an image was already heavily compressed before, additional compression yields diminishing returns.

Page speed is a confirmed Google ranking factor. Large images are the #1 cause of slow websites — they slow down load time, hurt Core Web Vitals scores (LCP in particular), and increase bounce rates. Compressing images before uploading them to your website can dramatically improve speed scores without any visible quality change.