Squeezr
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Compress PNG files in your browser

Reduce screenshots, UI exports, logos, and transparent graphics without sending them to a server. Squeezr runs pngquant and oxipng locally on your device.

What happens to a PNG

Squeezr decodes the image inside a Web Worker, reduces its colour palette with libimagequant, and then runs a lossless oxipng pass. The target quality is 80 with a quality floor of 65. If that floor cannot be met, the worker skips palette reduction and uses the lossless pass instead.

The output remains a PNG unless you turn on WebP. Transparent pixels stay in the pixel pipeline, and the before-and-after preview lets you inspect important edges, text, and alpha transitions before downloading.

How to compress a PNG

  1. Drop PNG files onto the compressor, choose them from disk, or paste a screenshot.
  2. Leave resize off to preserve dimensions, or choose a smaller percentage.
  3. Press Compress, inspect the result, then download one file or the complete ZIP.

When PNG is the right format

Keep PNG for interface screenshots, diagrams, icons, logos, line art, and graphics that need transparency or crisp edges. Photographs usually compress more efficiently as JPEG or WebP because they contain continuous colour and texture rather than a limited palette.

If a photo was saved as PNG, try WebP output and compare it visually. If the image must remain widely editable as PNG, leave the format toggle off.

Measured on the project fixtures

Flat UI PNG, 900×600
35 KB → 3.0 KB
91% smaller
Gradient-and-noise PNG, 700×500
753 KB → 173 KB
77% smaller

These are real project test fixtures, not guaranteed ratios. Savings depend on the image’s colours, dimensions, existing optimisation, transparency, and visual detail.

Privacy and safeguards

Image bytes and filenames stay in the browser. Files are processed sequentially to limit peak memory, and source images above 40 megapixels are rejected before encoding. When resize is off, Squeezr returns the original file if the compressed result would be larger.

Squeezr is an experimental personal tool. Keep the original file and verify any important output before replacing an archival or production asset.

PNG compression questions

Is the PNG compression lossless?

The palette-reduction stage is lossy, although it is designed to preserve visual quality. The oxipng stage is lossless. If the configured quality floor cannot be met, Squeezr falls back to the lossless-only path.

Are my images uploaded?

No. Compression happens through browser APIs, WebAssembly codecs, and a local Web Worker. Read the full privacy explanation for the exact boundary between initial app assets and your image data.

Can I compress a batch?

Yes. Add up to 20 PNG or JPEG files, process them sequentially, and download the completed batch as a timestamped ZIP.