Add up to 30 PNG images (up to 50 MB each) and compress them in your browser. The default lossless mode removes text and EXIF chunks and recompresses the image data with oxipng, so every pixel, the transparency and the bit depth stay exactly the same. Palette mode goes further by reducing the image to 8 to 256 colors, with optional dithering. Files that wouldn't get smaller are returned unchanged.
Compress PNG images losslessly and privately
This PNG compressor reduces file size without changing how the image looks, and it runs in your browser, so your images are never uploaded.
PNG is a lossless format used for graphics, logos, interface elements, screenshots and anything that needs transparency. It keeps every pixel exactly, which makes it ideal for sharp edges, text and flat colors. But many programs save PNG files with quick, light compression, and some add metadata, so the files end up larger than they need to be. Recompressing them often saves a noticeable amount with no change at all to the pixels.
PNG compression filters each row of pixels (with the None, Sub, Up, Average or Paeth filter) and then compresses the result with DEFLATE. The best filter depends on the content. oxipng tries different filter strategies and compression settings and keeps the smallest result, which takes more computing time than a normal save but gives smaller files with identical pixels.
When to compress PNG files
Compress PNGs to cut bandwidth, speed up pages, meet upload size limits, or make graphics lighter on phones. Screenshots, exports from design tools and images from older websites are often larger than necessary. Figma, Sketch and Adobe XD exports, for example, usually gain from a pass through an optimizer before deployment.
Interface screenshots, diagrams, logos with large transparent areas, and graphics with flat colors or straight lines compress best. Photos don't suit PNG; convert them to JPG, WebP or AVIF instead, which compress photos far better.
Lossless and palette modes
Lossless mode keeps the image identical, pixel for pixel. It removes text chunks and EXIF data, recompresses the image with oxipng, and keeps the original bit depth, palette and color profile.
Palette mode converts the image to an indexed PNG with at most the number of colors you choose (8 to 256, default 256), using a high-quality color quantizer, and then runs oxipng. Dithering, on by default, mixes palette colors to keep gradients smooth. Flat graphics and screenshots usually look the same and become much smaller. Photos and soft gradients can show banding, so check the preview.
PNG format details
PNG supports bit depths of 1, 2, 4, 8 and 16 bits per channel. An indexed PNG (often called PNG-8) stores up to 256 colors in a palette and can be much smaller than a full-color PNG (PNG-24 or PNG-32 with transparency) for graphics with few colors, but it's unsuitable for photos.
Transparency is stored in an alpha channel, so pixels can be partly transparent, not just on or off like GIF. Uniform transparent areas compress very well, which is why logos and icons with large transparent backgrounds shrink a lot.
Savings from lossless compression vary. Files that were already optimized gain little, while quick exports from screenshot tools and editors can shrink by a large margin. The output is always pixel-for-pixel identical in lossless mode.
FAQ: PNG Compressor
Do you upload my PNG images?
No. Compression happens in your browser, and your images never leave your device.
Will transparency be preserved?
Yes. Lossless mode keeps the alpha channel exactly, including partial transparency. Palette mode keeps transparency too, as part of the reduced palette.
Is PNG compression lossless?
In the default lossless mode, yes: the pixels are identical to the original, and only the way they are stored changes. Palette mode is lossy, because it reduces the number of colors.
How much can I reduce PNG file size?
It depends on how the PNG was saved. Unoptimized exports and screenshots often shrink noticeably in lossless mode, and already optimized files shrink little. Palette mode often makes graphics and screenshots several times smaller. Photos in PNG compress poorly in both modes.
Can I compress multiple PNG files at once?
Yes. Add up to 30 PNG files and compress them with the same settings. Download them one by one or as a ZIP.
What is the difference between PNG-8 and PNG-24?
PNG-8 stores up to 256 colors in a palette and suits simple graphics and logos. PNG-24 stores millions of colors and suits photos, gradients and complex graphics, with PNG-32 adding full alpha transparency. Lossless mode keeps whichever type your file already is, and palette mode produces a palette PNG.
Will this affect my animated PNGs?
The compressor is designed for still images. Palette mode keeps only the first frame of an animated PNG (APNG). If the animation matters, check the result before you replace the original, or keep the original file.
Does compression affect interlaced PNGs?
The output is saved without interlacing. Interlacing lets an image appear in rough passes while it loads, but it usually makes the file larger, and most sites don't need it.
Why do some PNGs compress better than others?
It depends on the content and on how the file was first saved. Large flat areas, straight lines and repeated patterns compress very well. Photos with noise and fine detail compress poorly as PNG and are better saved as JPG, WebP or AVIF.
Is there a file size limit?
Each PNG can be up to 50 MB and 64 megapixels, with up to 30 files per batch. Very large files take longer and use more memory on slower devices.