PNG Compressor

Shrink a PNG losslessly, or cut its palette when size matters more.

Up to 50 MB per file. Sign up free to compress files up to 100 MB.

How to compress PNG files online

PNG uses lossless compression by default, so standard tools barely reduce size. Our engine shrinks the pixel dimensions first and reduces the colours only if it has to.

  1. 1

    Upload PNG images

    Select your PNG screenshots, graphics, or logo files. Transparency (alpha channel) is fully preserved during compression. One file at a time on the free plan.

  2. 2

    Choose a target size

    Select a target size. The image is scaled down first with every colour kept. Only if scaling alone cannot reach the target is it reduced to a 256-colour palette.

  3. 3

    Download optimized PNGs

    Download your compressed PNGs with transparency intact. The output remains a valid PNG file, no format conversion needed. ZIP download available for batches.

What this compressor does well

Lossless compression

If the PNG already fits, it is only re-saved with DEFLATE, losslessly. Pixels and colours change only when your target needs them to.

Color quantization

Used only when scaling alone cannot reach the target: a 256-colour palette shrinks the file a long way, at the cost of smooth gradients.

Alpha transparency

Unlike JPG, PNG supports full 8-bit alpha transparency per pixel. Our compressor preserves every transparency level, so logos and overlays stay crisp.

Metadata stripping

PNG files can contain large text chunks, color profiles, and timestamps. Stripping these ancillary chunks alone can shave 10-20% off file size with zero visual impact.

Ideal for graphics

PNG excels at logos, icons, UI screenshots, diagrams, charts, infographics, text overlays, and any image requiring transparent backgrounds or pixel-perfect sharpness.

Resize before recolour

Scaling down keeps every colour, so gradients and anti-aliased text survive. A tight target shrinks the image, so check that small text is still readable.

Why a tight PNG target costs you resolution

PNG is lossless, so there is no quality dial to turn down, the only way to make one smaller is to store fewer pixels. That makes a tight target riskier than it looks. In our own testing a 2560x1440 screenshot asked for 50KB came back 575x323, small enough that the text was no longer readable, while the same file at 200KB kept a usable 1246x701. If your PNG is a photograph, converting it to JPG or WebP will beat any PNG compression by a wide margin; if it is a flat-colour logo it is probably already small enough to leave alone.

Upload limits worth knowing

The caps people most often run into, and what each one really means in practice.

Where Limit In practice
Gmail 25 MB Attachments above this are converted to a Drive link instead of sending.
Outlook.com 20 MB Outlook desktop against Exchange is often capped lower, at 10 MB.
WordPress (default) 2 MB Set by PHP's upload_max_filesize; many hosts leave the default in place.

Email attachments are Base64-encoded in transit, which inflates them by roughly 33%. A 20 MB file arrives as about 27 MB, so a 25 MB cap is really closer to 18 MB of actual payload. Leave headroom rather than compressing to exactly the published limit.

How PNG compression works

PNG is lossless: the file format cannot discard image data. To reach a smaller size the compressor first scales the image down with every colour kept, then, only if scaling alone cannot reach the target, reduces it to a 256-colour palette, which flattens gradients and can dither smooth areas. The output is always a PNG, with its transparency intact. For screenshots, diagrams, and logos with limited colours this works cleanly. For a photograph saved as PNG, converting it to JPG or WebP gives far more quality per kilobyte than any PNG target.

Which target size to pick for PNG

Different portals cap PNG uploads at different sizes. Pick the target that matches where you’re uploading rather than shrinking blindly, over-compressing wastes visible quality, under-compressing gets rejected.

Other targets

These have no page of their own. Pick the size in the upload box above.

50KB
Signatures, icons and flat-colour graphics. PNG stores every pixel losslessly, so 50 KB only works for images with few distinct colours: signatures, line art, icons, simple logos.
150KB
Logos, UI assets and screenshots with transparency. 150 KB fits a detailed logo or a UI screenshot while keeping the alpha channel intact.
1MB
Detailed graphics and full-window screenshots. 1 MB fits a large screenshot or a detailed graphic at full resolution, with every colour and the transparency kept.
2MB
High-resolution logo & press-kit assets. Press-kit PNGs for brand assets, hero logos, mascots, product renders, are usually delivered at 2000-3000 px width and land in the 1-3 MB range as PNG.

Frequently asked questions

How do I compress PNG files online?

Choose a target size, upload your PNG file, and click Compress. iFormat shrinks it to your chosen size while keeping quality as high as possible, free, no watermark, and no account needed.

What sizes can I compress PNG to?

Dedicated pages cover 100KB, 200KB or 500KB. Pick the size that matches the upload limit or email cap you need to meet.

How does PNG compression work?

A PNG stores pixels with DEFLATE, which is lossless, so re-running it on an already-optimised file saves very little. Reaching a size target therefore means removing something. Resampling comes first, at full colour, because dropping a few pixels costs less than dropping colours: the image is scaled down a step at a time until it fits. Only when scaling alone cannot reach the target is the image reduced to a 256-colour palette.

Will compressing reduce PNG quality?

Screenshots, UI mockups and graphics with flat colours survive both steps well: they rarely hold more than a few hundred colours to begin with, so a 256-colour palette is close to invisible and cuts 60–80%. A photograph stored as PNG is the hard case, because scaling it down loses detail and a palette puts visible banding into smooth gradients. Save photographs as JPG or WebP instead.

Is the PNG compressor free?

Yes. Compressing PNG files is free with no watermark and no sign-up. Paid plans only raise file-size and batch limits.

Are my PNG files kept private?

Yes. Uploads use an encrypted HTTPS connection, compression runs on an isolated worker, and both your original and the compressed file are deleted automatically within 1 hour, and nothing is stored, shared, or used for training.

Does PNG compression remove transparency?

No. The compressor preserves alpha-channel transparency. Transparent backgrounds, semi-transparent overlays, and variable opacity all survive compression unchanged.
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