Free TinyPNG Alternative: Compress PNG with Transparency

PNG is lossless, which is great for logos, icons and screenshots, but it also makes PNG files large. The well-known trick behind services like TinyPNG is colour quantization: most graphics use far fewer than the 16 million colours a PNG can store, so reducing the image to a carefully chosen palette of a few hundred colours or fewer shrinks the file dramatically while the picture looks almost identical. This page applies the same kind of lossy PNG compression, for free and entirely in your browser.

At the default quality of 75 each PNG is reduced to a 128-colour palette and the alpha channel is preserved, so transparent backgrounds and soft shadows stay intact. The optimizer also produces a normal lossless PNG and keeps whichever version is smaller. WoowTools is an independent service and is not affiliated with TinyPNG; the name only describes the type of compression.

How to use the TinyPNG Alternative: Smart PNG Optimizer

1. Drop your images onto the upload area, click it to choose files, or paste an image with Ctrl+V. This page accepts PNG files, many at once and up to 80 MB each.
2. Use the quality slider to set the palette size: 85 to 99 gives 256 colours, 70 to 84 gives 128, 50 to 69 gives 64, 30 to 49 gives 32 and lower values 16 colours; 100 saves a lossless PNG. The line under the slider shows the current colour count.
3. Need a fixed maximum size? Target size tries 256, 128, 64, 32 and 16 colours in turn and only reduces the dimensions if even 16 colours are too large.
4. Check the result with the before/after slider: drag the divider across the preview and read the new dimensions, file size, quality and percentage saved underneath. Any change to the settings re-processes every image automatically.
5. Download a single image, or use Download all (ZIP) for the whole batch. Under More options you can also set a DPI value and a file-name pattern with {name}, {w} and {h}.

Best results with palette PNG

• Logos, icons and UI graphics with flat colours compress extremely well, often without any visible change even at 64 colours.
• Screenshots of apps and websites shrink a lot; check small text with the before/after slider and raise the palette size if edges look rough.
• Photos saved as PNG show banding at low colour counts. Convert them with PNG to WebP instead, or save them as JPG with the TinyJPG-style optimizer.
• Fixed 256-colour output is also available on the PNG8 converter, and the general PNG compressor uses the same engine with other defaults.

Private, free and fast

The whole job runs in your browser: images are decoded, resized and re-encoded on your own device, so nothing is uploaded to a server. There is no sign-up, no watermark and no daily limit, and location and camera data (EXIF) are removed from every result.