Does compressing a PNG damage transparency?

No. The alpha channel survives palette quantization intact, including semi-transparent pixels like drop shadows and anti-aliased edges. You can check every result against a checkerboard in the compare view, so you verify the transparency instead of trusting a promise.

Is PNG compression lossless or lossy?

The PNG format is lossless, but the big savings tool is subtly lossy. That tool is palette quantization, the TinyPNG technique we also use. It reduces the palette to 256 or fewer expertly-chosen colours. On screenshots and graphics the difference is usually invisible. The slider lets you check.

Why is my PNG file so large?

Usually because it holds a photograph. PNG stores pixels faithfully, and photographs have millions of subtly-different colours. Our reference photo weighs 1382.4 KB as PNG and 74.2 KB as an equivalent JPEG. PNG earns its bytes on graphics, screenshots and transparency. Photos belong in JPEG, WebP or AVIF.

How much can a PNG realistically be reduced?

Measured, not promised: our photographic reference dropped −86% on Auto (1382.4 → 189.8 KB). A big UI screenshot dropped −85% (2683.7 → 394.8 KB). Flat-colour art compresses hardest. Photos vary most.

What is the difference between PNG-8, PNG-24 and PNG-32?

Bit depth. PNG-8 stores up to 256 palette colours (small), PNG-24 stores full truecolour (big), and PNG-32 is truecolour plus an alpha channel. Quantization converts 24/32-bit images toward 8-bit territory. That conversion is where the savings live.

Does converting to 8-bit keep the alpha channel?

Yes. Unlike GIF, PNG-8 supports full alpha per palette entry, so quantized output keeps real transparency, including soft edges. This misconception keeps people on heavyweight PNG-32 exports. The compare view will show you the alpha survived.

How do I get a PNG under 50 KB or 100 KB?

Set Max file size in Advanced settings. The cap is hard: we meet it by tightening quantization and, if needed, dimensions, and we never overshoot. For photographic content a cap that tight usually means the honest answer is switching format. The tool will tell you rather than deliver mush.

Can I compress the same PNG twice?

You can, but a second pass through quantization compounds palette reduction. It usually saves little and can band gradients. Better: keep your original and compress once per destination. If a re-run would grow the file, our never-larger guard returns your original untouched.

Why did my PNG get BIGGER after optimising elsewhere?

Common causes: a tool that re-encoded truecolour with heavier filtering, added metadata, or "optimised" an already-quantized file back to 24-bit. With us, same-format compression that would grow the file returns your original bytes untouched and says so.

Should this image even be a PNG?

Screenshots, UI, logos, anything transparent: yes. Photographs: almost never. The same photo measured 189.8 KB as optimised PNG but 69.8 KB as AVIF. If your PNG is a photo, converting beats compressing by an order of magnitude.

Can I compress many PNGs at once?

Yes, up to 50 per batch at 30 MB each. You get one ZIP with filenames preserved, free, with no signup and a 300-image daily allowance. Each row shows its measured before/after size, so a screenshot-heavy docs folder shows exactly where the bytes went.

What happens to my files?

We keep nothing. We process your files, then wipe them automatically. We never archive them or use them for anything else. We strip metadata from outputs by default, and you need no account.

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Compress PNG

Compress PNG files in your browser while keeping them as PNG. The image stays lossless with its transparency intact, just at a smaller file size.

Output format

– / –

Drop images or browse

JPEG · PNG · WEBP · AVIF · HEIC · max 30 MB

HEIC

PNG

JPEG

AVIF

WEBP

Advanced settings

QualityAuto

SmallerAutoBetter

Auto tunes each image.

Max file size

A hard cap for “under 50 KB” portals.

Max resolution

Empty side keeps the ratio. Never enlarges.

Keep EXIF metadataOff by default. We strip camera and GPS data.

One real file, before and after

PNG, 1.3 MB — A real result from this exact operation: 1.3 MB in, 185 KB out. Drop your own file and the meter reports yours. The left half is a preview render; the byte counts are the real files’.

PNG, 185 KB — A real result from this exact operation: 1.3 MB in, 185 KB out. Drop your own file and the meter reports yours. The left half is a preview render; the byte counts are the real files’.

What PNG compression actually saves, by content type

Source	Original	Compressed	Saved
UI screenshot	2683.7 KB	394.8 KB	−85%
Photograph	1382.4 KB	189.8 KB	−86%

Auto quality. The photo row is an honest warning. The next section explains why photos don't belong in PNG at all.

How these numbers are measured: every byte count on this page is the size of the actual encoded file our engine produced from the named source image. Those are the same bytes you would download, not an estimate or a best case. Rerun any of them yourself: drop your own file into the tool above and the meter reports your real result.

The trick with a name: palette quantization, explained

A truecolour PNG can address 16.7 million colours. Most real images use a fraction of them well. Quantization rebuilds the image from up to 256 expertly-chosen colours, with dithering to hide the seams. It is the technique behind every "smart PNG" service, and we run it with tuned settings. Competitors bury two facts. First, quantization is technically lossy even though PNG-the-format is lossless. On screenshots and flat art you almost never see it. On subtle gradients you sometimes do, which is what the compare view is for. Second, PNG-8 keeps full alpha, so "quantized" never means "lost my transparency".

If your PNG is a photograph, stop: convert it instead

The most valuable byte advice on this page: PNG spends its bytes guaranteeing pixel-exactness that photographs don't need. We measured the same reference photo: 1382.4 KB as original PNG, 189.8 KB as our best compressed PNG, but 74.2 KB as JPEG and 69.8 KB as AVIF at matched viewing quality. Converting beats compressing by an order of magnitude: PNG to JPG for universal compatibility, PNG to AVIF for the web. Keep PNG for what needs it: transparency, screenshots, art with hard edges.

Transparency: preserved, and provable

Every output keeps the alpha channel: full and semi-transparency, soft shadows, anti-aliased edges. The compare view renders your image over a checkerboard exactly so you can check this claim instead of taking our word for it. Drag the wipe across a logo's edge and watch for fringing. You won't find any. If a downstream tool shows white corners, that tool flattened the alpha. The file we gave you still has it.

When not to compress a PNG

It is a design master or archival file? Keep it truecolour and untouched. Quantize the copies you ship, never the source.
Print-bound graphics? Print magnifies banding that screens hide. Send the printer the unquantized file.
A photograph? Convert, don't compress. JPEG/WebP/AVIF beat any PNG by an order of magnitude on photos.

Questions, answered

Short answers specific to this page. The tool above settles most of them in a second.

Does compressing a PNG damage transparency?: No. The alpha channel survives palette quantization intact, including semi-transparent pixels like drop shadows and anti-aliased edges. You can check every result against a checkerboard in the compare view, so you verify the transparency instead of trusting a promise.
Is PNG compression lossless or lossy?: The PNG format is lossless, but the big savings tool is subtly lossy. That tool is palette quantization, the TinyPNG technique we also use. It reduces the palette to 256 or fewer expertly-chosen colours. On screenshots and graphics the difference is usually invisible. The slider lets you check.
Why is my PNG file so large?: Usually because it holds a photograph. PNG stores pixels faithfully, and photographs have millions of subtly-different colours. Our reference photo weighs 1382.4 KB as PNG and 74.2 KB as an equivalent JPEG. PNG earns its bytes on graphics, screenshots and transparency. Photos belong in JPEG, WebP or AVIF.
How much can a PNG realistically be reduced?: Measured, not promised: our photographic reference dropped −86% on Auto (1382.4 → 189.8 KB). A big UI screenshot dropped −85% (2683.7 → 394.8 KB). Flat-colour art compresses hardest. Photos vary most.
What is the difference between PNG-8, PNG-24 and PNG-32?: Bit depth. PNG-8 stores up to 256 palette colours (small), PNG-24 stores full truecolour (big), and PNG-32 is truecolour plus an alpha channel. Quantization converts 24/32-bit images toward 8-bit territory. That conversion is where the savings live.
Does converting to 8-bit keep the alpha channel?: Yes. Unlike GIF, PNG-8 supports full alpha per palette entry, so quantized output keeps real transparency, including soft edges. This misconception keeps people on heavyweight PNG-32 exports. The compare view will show you the alpha survived.
How do I get a PNG under 50 KB or 100 KB?: Set Max file size in Advanced settings. The cap is hard: we meet it by tightening quantization and, if needed, dimensions, and we never overshoot. For photographic content a cap that tight usually means the honest answer is switching format. The tool will tell you rather than deliver mush.
Can I compress the same PNG twice?: You can, but a second pass through quantization compounds palette reduction. It usually saves little and can band gradients. Better: keep your original and compress once per destination. If a re-run would grow the file, our never-larger guard returns your original untouched.
Why did my PNG get BIGGER after optimising elsewhere?: Common causes: a tool that re-encoded truecolour with heavier filtering, added metadata, or "optimised" an already-quantized file back to 24-bit. With us, same-format compression that would grow the file returns your original bytes untouched and says so.
Should this image even be a PNG?: Screenshots, UI, logos, anything transparent: yes. Photographs: almost never. The same photo measured 189.8 KB as optimised PNG but 69.8 KB as AVIF. If your PNG is a photo, converting beats compressing by an order of magnitude.
Can I compress many PNGs at once?: Yes, up to 50 per batch at 30 MB each. You get one ZIP with filenames preserved, free, with no signup and a 300-image daily allowance. Each row shows its measured before/after size, so a screenshot-heavy docs folder shows exactly where the bytes went.
What happens to my files?: We keep nothing. We process your files, then wipe them automatically. We never archive them or use them for anything else. We strip metadata from outputs by default, and you need no account.

Related conversions

Every route in and out runs on the same engine and the same rules. Each card is its own page.

Ready when your file is

Drop it in above. The meter reports the exact saving before you download anything.

Compress now