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ImageZap

Compress PNG

Reduce the size of your PNGs without changing a single pixel. They keep transparency and remain standard PNGs.

Drop your images here

or paste with Ctrl+V · JPG, PNG, WebP, AVIF, JXL, GIF, HEIC · up to 30 MB each

Images are processed on your device and stored only in this browser so you can convert them again.

Lossless PNG compression

PNG uses the DEFLATE algorithm, the same one used by ZIP files. Most programs apply it with fast, generic settings and also store metadata chunks that aren't needed to display the image. OxiPNG —the optimizer ImageZap uses— tries different filters per row, reduces bit depth or palette when possible and re-compresses the data with more effort.

The result is a PNG pixel-identical to the original, typically 10–40% smaller. On screenshots exported by the operating system the savings can be larger.

How to compress PNG

  1. Add your PNG files (or paste a screenshot with Ctrl+V).
  2. The output format is set to Original, so each PNG is optimized as PNG.
  3. For more reduction, raise the effort under Advanced: it takes longer but squeezes more out.
  4. Download the optimized files.

Need more reduction?

Because PNG is lossless, there's a limit to how much it can be compressed. If the file is still too big:

  • Resize. A screenshot on a Retina display has twice as many pixels per side as its display size.
  • Try lossless WebP. Same pixels, usually 25% smaller. Select WebP alongside Original to compare in one pass.
  • For photos, switch format. A photo saved as PNG will be far smaller as JPG, WebP or AVIF.

Optimized PNG and the web

Optimized PNGs are ideal for technical documentation, UI, diagrams, screenshots with small text and any asset where a compression artifact would be obvious. They're also the safe choice when the destination doesn't accept modern formats.

Frequently asked questions

Does compressing PNG reduce quality?

No. Optimization with OxiPNG is lossless: the pixels are exactly the same.

Is transparency preserved?

Yes, the alpha channel is kept. Fully transparent pixels are also normalized to compress better without changing the appearance.

Why do some PNGs barely shrink?

Because they were already optimized, or because they're photos, which PNG can't compress much further without losing information.

Does it work like TinyPNG?

Not exactly. TinyPNG reduces the color palette (lossy). ImageZap keeps all colors; for bigger savings, use WebP or AVIF.

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