Compress PNG

How it works

Tap or click the box and choose your PNG file; only .png files are accepted and you can select several. The tool opens the file on your device, reduces its colors to the number you picked and writes it back as an 8-bit palette PNG. Transparent backgrounds and soft edges survive because the palette stores transparency too; width and height do not change. There is one setting. 256 colors is usually impossible to tell apart from the original, even on photos with smooth gradients; 64 colors gives the biggest saving on logos, icons and screenshots, which only use a handful of colors anyway. "Lossless" leaves every pixel untouched and only redoes the compression, so the saving is small and sometimes zero. Example: a 1920×1080 full-color screenshot can weigh several hundred kilobytes up to a megabyte; with 64 colors it usually drops below half. The result line shows old and new size, the percentage and the dimensions, and tells you if the file grew — in that case keep the original. Every run starts from your original file.

This tool is also known as compress png, png compressor, reduce png file size, compress png without losing transparency, make png smaller, png optimizer online.

What is Palette PNG (8-bit PNG)?

A palette PNG stores each pixel as a number pointing into a table of at most 256 colors at the start of the file, instead of storing the full color. A full-color PNG uses 3 or 4 bytes per pixel, a palette PNG uses 1, so the same image can end up at a third or a quarter of the size. A transparency table (tRNS) can be attached to the palette, which lets every color carry its own opacity: a logo's soft edge stays semi-transparent. This page converts images to that kind of PNG; the result opens like any other PNG in browsers, phones and design apps.

What is Color quantization?

Color quantization merges the thousands of distinct colors in an image into the closest few, down to the number you choose. A good quantizer spends its palette where the image actually has detail: a picture that is mostly blue sky gets mostly blues. On images with few colors — logos, icons, interface screenshots — nothing visible is lost because the image never had that many colors. On photos, going below 64 colors can leave visible bands in smooth gradients; pick 256 there, or convert the photo to JPG.

What is the difference between PNG compression and image compression?

The image compressor writes everything as JPG. That works very well on photos, but transparent areas turn white and the result is no longer a PNG. PNG compression keeps the file a PNG; the saving comes from reducing the number of colors, and transparent backgrounds and semi-transparent edges are kept. Use this page for logos, icons, screenshots, stickers and web graphics, and the image compressor for camera photos without transparency. You can compress a photo as PNG, but a JPG of the same visual quality is usually smaller.

Why PNG files are large and where this tool loses detail

PNG is lossless: it stores every pixel exactly, and its own compression (deflate) has already been applied. There is no JPG-style quality slider for PNG, so a real saving only comes from simplifying the content. This tool simplifies the colors: a full-color PNG can use 16 million colors, the output keeps at most 256. On images with few colors that is invisible; on sky, skin tones and shadows, going below 64 colors can leave visible bands.

Transparency is kept, but it also goes into the palette: soft edges are drawn with fewer opacity steps, which most screens do not show. With "Lossless" no pixel changes; the saving only comes from recompressing, and a file already well optimized by a design app can even grow. The result line says so — keep the original or choose fewer colors.

Which setting for which image?

Logos, icons, images with text and screenshots: 64 colors. These are made of a few flat colors, so the saving is large and the loss invisible. Web graphics, illustrations and interface images: 128 colors. Product photos on a transparent background or images with soft shadows: 256 colors; gradients survive and the file still often halves.

For camera photos without transparency this is the wrong page: converting to JPG gives a much smaller file that looks the same, so use the image compressor. If the file has to fit a limit (for example a 500 KB upload form), try 256 first, then 128 and 64; to shrink the dimensions as well, run the image resizer first and come back here.

Frequently asked questions

Does compressing a PNG remove the transparent background?

No. The result is still a PNG and transparency is stored in the palette, so transparent areas stay transparent and soft edges stay semi-transparent. Transparency is lost when a PNG is converted to JPG, because JPG has no transparency; this tool never converts to JPG.

Can I compress a PNG without losing quality?

Partly. "Lossless" redoes the compression without changing a single pixel, but the saving is usually small. The real saving comes from reducing colors: 256 colors is visually identical on most images, so it looks lossless in practice, although the pixels are not bit-for-bit the same.

Which is smaller, PNG or JPG?

For camera photos, JPG is almost always smaller. For logos, icons, images with text and screenshots, a palette PNG is often smaller than a JPG and sharper, and it keeps transparency. If your image has transparent areas or crisp text, stay with PNG.

Is my file uploaded anywhere?

No. The PNG never leaves your device: decoding, color reduction and writing all happen inside your browser, and the page keeps working if you go offline after it loads. Very large images can take a few seconds on a phone because your device does the work, not a server.