The Free PNG Compressor That Genuinely Shrinks PNGs
A good online PNG compressor should hand you back a smaller PNG — not a re-labelled copy. This png compressor decodes your image, reduces its color palette with smart quantization, and re-encodes it as a compact indexed PNG, then runs a lossless oxipng pass to squeeze out the last bytes. Transparency is kept and the dimensions are never changed, so what you download is the same picture at the same size, just lighter.
Everything happens in your browser through WebAssembly. When you use this online png compressor your files are processed entirely on your own device and are never uploaded to a server — it is faster (no upload wait), private, and free with no sign-up and no watermark.
Lossy vs Lossless PNG Compression
A PNG compressor can work two ways, and this tool offers both:
- •Lossy (palette quantization) — reduces the image to 256 colors or fewer and saves it as an indexed PNG. This is how tools like TinyPNG and compresspng achieve 50–80% smaller files. It is ideal for logos, icons, illustrations, UI assets and screenshots, where the eye barely notices the reduced palette.
- •Lossless (oxipng) — re-packs the PNG without touching a single pixel. The savings are smaller (often 5–30%, depending on how the file was exported) but the output is mathematically identical to the original. Use it when you need exact pixels or crisp text with no risk of banding.
Why PNG Files Get So Big
PNG is a lossless, true-color format: every pixel is stored exactly, which is what makes it perfect for sharp edges, text and transparency — and also what makes it heavy for photographs and smooth gradients. A png compressor recovers most of that weight by cutting the color palette down to what the image actually needs. For a photo with no transparency, though, no PNG will beat a JPG or WebP, so the smartest move is sometimes to convert rather than compress.
When to Use a PNG Compressor (and When to Convert)
- •Logos, icons and UI assets — compress as PNG to keep crisp edges and transparency
- •Screenshots with text and flat-color illustrations — quantization shrinks these the most
- •Transparent graphics for web, apps and e-commerce — PNG keeps the alpha channel
- •Photographs or detailed gradients with no transparency — convert to JPG or WebP instead; they will be far smaller than any PNG
Tips to Compress PNG Without Losing Quality
- •Resize to the dimensions you actually display first — a 3000px logo shown at 300px wastes most of the file.
- •If quantization shows banding in a smooth gradient, switch to lossless mode for that image.
- •Compress once from the original export rather than re-compressing an already-processed file.
- •Compressing a whole icon set? Use batch mode and download everything as a single ZIP.
PNG Compressor — Frequently Asked Questions
What is a lossy PNG compressor?
A lossy PNG compressor shrinks a file by reducing its color palette — our png compressor quantizes the image to 256 colors or fewer and re-encodes it as an indexed PNG. The eye barely notices the difference on logos, icons and graphics, but the file gets dramatically smaller. If you need every pixel untouched, switch to the lossless mode instead.
Can this PNG compressor convert a PNG to JPG?
No — this png compressor keeps your file as a PNG so transparency is preserved. If your image is a photograph with no transparency, converting it to JPG or WebP will usually be smaller than any PNG; use our image converter for that. For logos, screenshots and graphics that need transparency, stay with PNG and compress here.
Is PNG compression lossless?
It can be both. By default this png compressor uses lossy palette quantization for the biggest size reduction, then runs a lossless oxipng pass to squeeze it further. If you need a pixel-perfect result, use the lossless mode — it only applies oxipng optimization and never changes a single pixel.
Does compressing a PNG keep transparency?
Yes. Alpha transparency is fully preserved through both the quantization and the lossless optimization steps, so transparent logos and icons stay transparent after compression.
Are my images uploaded to a server?
No. This online png compressor runs entirely in your browser using WebAssembly, so your images never leave your device and nothing is stored on a server.
Can I compress several PNG files at once?
Yes. Batch mode lets you compress multiple PNG images together and download them all in a single ZIP file — handy for icon sets, product galleries and asset folders.