Compress PNG Files

Shrink a whole folder of PNGs — usually by 60–75% with no visible change, transparency kept. Free, no account, and nothing is uploaded.

Drop your images here

or select them from your computer — up to 200 at a time

You can also paste images with Ctrl+V

Supported formats: JPG, PNG, WebP, BMP, GIF or AVIF in — JPG, PNG, WebP or AVIF out · max 30 MB per fileUp to 200 files · nothing is uploaded

BMP and GIF are read and come back as JPG, PNG, WebP or AVIF — this tool has no encoder for them. Animated files are not accepted.

Compress by

Options unlock once your images are added.

How to use

  1. Add your PNG files

    Drop a folder onto the box above, or press Select images. Up to 200 at a time; they stay on your machine.

  2. Choose Smart or Lossless

    Smart is much smaller and right for logos, screenshots and product shots. Lossless keeps every pixel.

  3. Compress and download

    Every file lists its size before and after. Compare any one with its original, then take the batch as a ZIP.

Why PNG files are so large

PNG is lossless: it records every pixel exactly, in as many colours as the image has. That is ideal for editing and wasteful for publishing — a screenshot or a cut-out product photo can carry tens of thousands of colours that nobody can tell apart, plus compression that the program which saved it never bothered to tighten. Most generic compressors cannot touch a PNG at all: a browser’s own encoder ignores quality for PNG, so they hand the file back unchanged.

Smart: a 256-colour palette

Smart picks the 256 colours that best represent each image, maps every pixel to the nearest one, and then recompresses the result with oxipng. For flat graphics, logos, screenshots and product shots on a plain background the difference is invisible and the file is typically 60–75% smaller; transparency is kept in the palette. Smooth photographic gradients are the exception — they can band — so use Compare on any photo before you keep it.

Lossless: every pixel kept

Lossless changes nothing in the picture and only redoes the compression, which saves up to about 20% on a typical PNG and very little on one that was already optimised. Choose it for images that must stay pixel-exact: assets you will edit again, technical drawings, or anything a later step will compare byte for byte.

PNG or another format?

If your PNGs are really photographs, the biggest saving is not to keep them as PNG: the same page can write JPG, WebP or AVIF under Output format, and aim each at a size in KB. This page is the bulk image compressor with PNG in mind; to change the width and height as well, use the bulk image resizer first.

Frequently asked questions

How much smaller will my PNGs get?
With Smart, the default, logos, product shots and screenshots typically shrink by 60–75%: they are reduced to a palette of up to 256 colours and recompressed, with no visible change. Lossless keeps every pixel exactly and saves up to about 20%. If a result is not smaller, the original PNG is returned unchanged.
Is transparency kept?
Yes. Both modes keep the alpha channel: Smart stores transparency in the palette, Lossless keeps it exactly as it was.
When should I not use Smart?
For photographs and smooth gradients. 256 colours can show as faint banding in a sky or a soft shadow — check with Compare. For photos, Lossless or converting to JPG, WebP or AVIF is the better choice.
Can I compress PNGs to a size in KB?
Not as PNG: a PNG has no quality setting to lower, so there is nothing to search. Choose JPG, WebP or AVIF as the output format and switch to Target size to aim for a number of KB.
Are my images uploaded?
No. The PNGs are compressed in your browser by encoders compiled to WebAssembly, running in a background worker, and never leave your computer.