How to Compress Images Without Losing Quality (Free)
Learn how to reduce image file sizes by 30–70% without noticeable quality loss. Free browser-based image compressor — no upload to server.
Large images slow down websites, fill up email inboxes, and exceed social media upload limits. But compressing images doesn't mean sacrificing quality. Modern compression algorithms reduce file sizes by 30–70% while keeping images visually indistinguishable from the originals.
Lossy vs. Lossless Compression
Lossy compression discards some image data that's invisible to the human eye — a 2MB JPEG can become 400KB with minimal visual change. Lossless compression preserves every pixel but achieves smaller reductions (10–25%). For web images and social media, lossy compression is the standard choice.
When to Compress Images
Compress images before uploading to your website (Google's PageSpeed score depends heavily on image sizes), before emailing attachments (most inboxes have 25MB limits), before uploading to social media (smaller files upload faster), and before storing in cloud drives to save space.
How Much File Size Reduction to Expect
JPG images typically compress 40–60% without visible quality loss. PNG images with large areas of solid color can compress 50–70%. WebP images are already efficient but can still be compressed another 20–30%. Results vary based on image content — photos compress better than screenshots with text.
Privacy: Does the Compressor See My Images?
This is the most important question when choosing an image compressor. Many online tools upload your images to their servers for processing. Browser-based compressors process everything locally — your images never leave your device. Always check the privacy policy.
Compress Your Images Now
The Image Compressor on Zerocosttools runs entirely in your browser — your images are never uploaded to any server. Upload JPG, PNG, or WebP files, see the before/after file sizes side by side, and download the compressed versions instantly. Free, private, and unlimited.