PDFixel

PNG Compressor

Advanced Settings

Preset Level

Estimated ~30-50% reduction

Quality Target75%

10%100%

PNG is lossless, so quality applies only when converting to WebP or AVIF. For PNG, size comes from the preset level, resizing and colour reduction.

Learn & Help

How to Compress PNG Images with Transparency

1Upload PNG
Drop your PNG graphics or screenshots into the workspace.
2Select Compression Mode
Choose Lossless compression or 8-Bit Color Quantization for maximal savings.
3Download Optimized PNG
Save your lightweight PNG with full transparency intact.

8-Bit Palette Quantization: Reduces color depth using Floyd-Steinberg dithering for massive size savings.
Lossless OxiPNG Mode: Compresses PNG deflater tables with zero visual change.

8-Bit Palette Quantization
Reduces 32-bit colors to an optimized 256-color palette with dithering for up to 70% size reduction.
Alpha Channel Preservation
Guarantees transparent margins and semi-transparent shadows stay clean.
Side-by-Side Quality Compare
Verify pixel clarity before downloading with our split view inspector.
Zero Cloud Uploads
Compress proprietary UI mockups and logos strictly on your device.

It converts 32-bit RGBA channels to an indexed 256-color palette while applying spatial error diffusion (dithering), preserving smooth color gradients without banding.

Because PNG has no quality dial to turn. It is a lossless format, and the browser canvas encoder ignores the quality argument outright when the output is PNG — any tool presenting you a PNG quality slider is presenting a control that does nothing. Real PNG compression therefore has exactly two levers: reduce how many distinct colours the file has to describe, which is what palette quantisation does, and reduce how many pixels there are, which is resizing. This tool uses the first; Resize PNG uses the second.

It depends entirely on what the image contains. Flat graphics — logos, icons, diagrams, UI screenshots — usually contain well under 256 distinct colours already, so quantisation is close to free and the savings are large. Photographs and smooth gradients contain tens of thousands, and forcing them into 256 shows up as banding or dither speckle in skies and skin tones. Use the before-and-after comparison on your own image rather than a rule of thumb.

Usually not. PNG was designed for images with sharp edges and flat colour and it stores photographs very inefficiently — the same photo as a good-quality JPEG or WebP is routinely five to ten times smaller with no visible difference. If your PNG is a photo or a screenshot of one, converting the format will beat any amount of PNG compression. Keep PNG for anything needing transparency or genuinely lossless pixels.

PNG Compressor

Shrink PNG graphics and screenshots without losing transparent alpha channels.

Drop PNG image(s) here

or click to browse • Up to 50 PNG files

Max 100MB per fileUp to 50 files

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