Does it keep transparency?

Yes. Fully transparent areas stay fully transparent and soft, semi-transparent edges are kept in the palette. Opaque pixels are never made see-through.

Why did my PNG not get smaller?

Some PNGs are already palette-optimised, for example files that went through TinyPNG or pngquant. When nothing we produce is smaller, you get the original back rather than a bigger file.

Are my PNG files uploaded to a server?

No. Your file is read into browser memory, processed on your own device, and released when you close the tab. Nothing is transmitted, stored, or logged at any stage.

Is there a file size limit?

There is no server-imposed cap because the work happens locally. The practical ceiling is your device memory: very large images (tens of megapixels) can be slow or fail on phones.

Which browsers support this PNG compressor?

Current Chrome, Edge, Firefox and Safari 16.4 or later. Older browsers without the CompressionStream API fall back to a plain lossless re-save, and still never return a larger file.

Updated for 2026 • 100% Free Online Image Tool

Free PNG Image Compressor Online

This PNG compressor reduces the image to a palette of at most 256 colours with dithering and writes an indexed PNG, keeping transparency. Screenshots and graphics typically shrink by 25% to 70%, photos saved as PNG by more. If the result would not be smaller, you get your original file back.

Select or drop your png image

100% free with zero file uploads. Processed locally in your web browser.

100% Client-Side Private Processing

Your files are processed locally on your own device. Zero server uploads, zero file storage, and zero tracking.

Zero Server Logs

How PNG Compression Works

Palette reduction: PNG is lossless, so re-saving it barely changes the size. The real saving comes from cutting the image to 256 colours or fewer and storing each pixel as a palette index.
Quality slider sets the colour count: from 16 colours at the lowest setting to 256 at the highest. If the chosen count would visibly band the image, more colours are used automatically.
Images that already use 256 colours or fewer are rewritten as an exact palette with no pixel changed.
Never larger: if no result beats your original, the original is handed back unchanged and the page says so.
100% client-side: the image is processed in browser memory and never uploaded.

Step by step

How to COMPRESS PNG Files in 3 Steps

1
Upload PNG Image
Drag and drop your PNG file into the compressor area.
2
Set the Quality
Lower quality means fewer colours and a smaller file. The default suits most screenshots and graphics.
3
Download Compressed File
Compare the before and after sizes shown, then save the PNG.

Common Questions

Frequently Asked Questions

Everything you need to know about the free online PNG compress tool.

Palette reduction is lossy, but dithering hides most of it, and the tool refuses a palette that measurably bands the image. Logos, icons and screenshots usually look identical. Smooth photographic gradients are the hardest case; for photos, converting to JPG or WebP saves far more.

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