Compress PNG
Compress PNG images in your browser — smaller files at the quality you choose, nothing uploaded. Free, unlimited, and private by design.
How to compress an image
- Drop or pick a PNG file — or paste it with Ctrl/⌘+V.
- Choose lossy for the smallest file or lossless to keep every pixel, then tune the quality.
- Compress, preview the before/after, and download — all on your device.
Why compress?
PNG is a lossless format with an alpha channel — pixel-perfect for logos, screenshots and line art. Compressing your PNG files makes pages load faster, lifts Core Web Vitals and cuts bandwidth — without a visible drop in quality when done right. Lossy reduces to a smart palette (imagequant) for big savings; lossless optimizes with oxipng for byte-for-byte identical pixels.
OptImg compresses PNG locally with the same Rust codecs used server-side elsewhere, so you get the savings without the upload wait, the queue, or handing your images to a third party. If a file is already well optimized, we tell you and keep your original instead of handing back something larger.
Frequently asked questions
- Are my PNG images uploaded to a server?
- No. PNG compression runs entirely in your browser with WebAssembly — your image never leaves your device, and there are no size or file-count limits.
- What's the difference between lossy and lossless?
- Lossy gives the smallest files by discarding detail you're unlikely to notice; lossless only removes redundancy, keeping the image identical. Lossy reduces to a smart palette (imagequant) for big savings; lossless optimizes with oxipng for byte-for-byte identical pixels.
- Does compressing PNG keep transparency?
- Yes. PNG transparency is fully preserved through compression.