How to use this PNG compressor
- Drop your PNG files onto the box above, or press Browse files to select them.
- Pull the colour reduction slider down and watch the saving grow. Stop when banding appears.
- Reduce the scale as well if the image is larger than it needs to be on screen.
- Press Compress PNG files and let the batch finish.
- Compare each preview against the reported saving, then download individually or as a ZIP.
What this compressor does
- Keeps the alpha channel intact, so transparent graphics stay transparent.
- Reduces the colour palette progressively rather than jumping straight to 256 colours.
- Combines colour reduction with optional scaling for much larger savings together.
- Shows the finished dimensions alongside the size change for every file.
- Works on screenshots, logos, icons, charts and interface exports.
- Never uploads anything and never adds a watermark.
Why PNG compression is a different problem
JPEG has a quality dial because it is lossy by design, you tell it how much detail to discard. PNG has no such dial. It is lossless: the file that comes out must reproduce every pixel that went in, so the only way to make it meaningfully smaller is to give it less to describe in the first place.
That is what this tool does. Reducing the bits per colour channel means the image contains fewer distinct colours, and a PNG with fewer colours compresses dramatically better because its internal filtering finds far more repetition to exploit. Scaling down removes pixels outright. Both are visible changes you choose to accept, which is more honest than a slider that pretends to be free.
Which images respond well
- Logos, icons and flat illustrations, which often use a handful of colours already.
- Interface screenshots, where large regions share exactly the same background tone.
- Charts, diagrams and line art with clean fills and no gradients.
- Pixel art and simple game assets, which were designed around a limited palette.
Photographs are the poor case. They contain millions of subtly different colours, and reducing that range produces visible banding in skies and skin long before the file gets usefully smaller. For a photographic PNG, the correct answer is not compression at all. It is converting to JPG, which typically saves ninety per cent or more with no visible loss.
Reading the colour reduction slider
At 8 bits per channel the setting is off and the image is untouched. At 6 bits you have 262,144 possible colours instead of 16.7 million, which is invisible on most graphics and already reduces the file noticeably. At 4 bits the palette is coarse enough that gradients begin to band, though flat artwork still looks perfect. At 2 bits the effect is deliberate and stylised.
The right approach is to start high, look at the saving, and step down until you can see the change. Different images have very different tolerances, and the preview alongside each result makes the trade-off obvious rather than theoretical.
Scaling is the bigger lever
If a PNG is 3000 pixels wide and will be displayed at 600, no amount of palette work compares to simply making it smaller. Pixel count falls with the square of the scale, so reducing to 50 per cent leaves a quarter of the data before any compression is applied. Combining a modest scale reduction with modest colour reduction usually beats pushing either one to its limit.
For precise dimensions rather than a percentage, the image resizer lets you type exact pixel values and lock the aspect ratio.
Transparency and privacy
The alpha channel is preserved throughout, so a logo compressed here still drops cleanly onto any background. That is the main reason to stay with PNG rather than converting; if transparency does not matter, WEBP through the general image compressor gives both small files and an alpha channel.
Nothing is uploaded. Files are decoded, adjusted and re-encoded inside your browser tab, so the design assets and internal screenshots people compress most often never reach a server.