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Free Online PNG Image Compression

Smaller PNGs, faster loads

ImageTool.app's online PNG compressor greatly reduces PNG file size with virtually no quality loss, down to under 1MB. Everything runs locally — no upload required.

Choose Image

Unoptimized PNGs are often 1–2x larger than they need to be. ImgZilla analyzes the palette structure locally in your browser, removes redundant metadata and applies smart quantization to shrink file size dramatically while fully preserving transparent pixels — images are never uploaded to any server.

Lossless PNG compression

Alpha channel always protected

Transparent PNGs are easily wrecked by poor compressors. We make alpha handling the top priority, so transparent areas stay pristine.

Palette optimization, no banding

PNG8 quantization tends to band on gradients. We use perceptual quantization to trim the palette almost imperceptibly while keeping visible detail.

Batch-compress PNG folders

The desktop app compresses an entire Figma / Sketch export directory at once — dozens of icons in seconds.

Built for Core Web Vitals

Google's LCP penalizes oversized images. Compressed PNGs load 3–5x faster, directly improving your Lighthouse score.

How to compress PNG

1

Drop in a PNG

Works with logos, UI screenshots, icons, product shots and Figma / Sketch exports — transparency detected automatically.

2

Download the PNG

Format and transparency unchanged, file size much smaller — no format conversion needed.

FAQ

Will compression break a transparent PNG?

No. ImgZilla specifically protects the alpha channel data throughout compression, so transparency is always preserved.

How small can a PNG get?

Logos and icons typically shrink 10–20%, screenshots and photos often 20–30%, depending on image complexity.

Should photos be PNG or JPG?

Photos are better as JPG. PNG is best for images with transparency, text, sharp edges or large flat color areas.

Can I compress PNG without quality loss?

Yes. Lossless compression only removes metadata and optimizes file structure, with zero quality loss.

Mac Desktop App

Download ImgZilla for faster batch compression

Want faster batch compression and stronger privacy? The ImgZilla desktop app does everything locally on your Mac — just drag and drop.

Download ImgZilla for FreeLearn more →
  • 100% local processing — images are never uploaded
  • Multi-threaded batch compression, up to 90% smaller
  • Originals auto-backed up to Trash, recoverable anytime
  • Compare before and after with the built-in image compare tool