Compress PNG Images Online
Reduce PNG file sizes by up to 80%. Fast, free, and completely private — no server uploads required.
Drop images here or click to upload
PNG — up to 50MB each
Lossless and lossy PNG compression options
Reduce PNG sizes by up to 80%
Maintains transparency in PNG files
Batch compress multiple PNGs at once
Convert PNG to smaller formats like WebP or JPG
100% client-side — images stay on your device
Understanding PNG Compression
PNG (Portable Network Graphics) is a raster image format that supports lossless data compression and transparency. It was created as an improved, non-patented replacement for GIF and is widely used for graphics, logos, screenshots, and images that require transparency.
How PNG Compression Works
PNG uses a two-stage compression pipeline. First, a prediction filter analyzes each row of pixels and encodes the differences between neighboring pixels (using Sub, Up, Average, or Paeth filters). This preprocessing step makes the data more compressible. Then, the filtered data is compressed using DEFLATE — the same algorithm used by ZIP files — which combines LZ77 dictionary matching with Huffman coding.
Compresso goes further by applying quantization (reducing the color palette) for lossy PNG compression, which can achieve dramatically smaller files — often 60–80% reduction — while maintaining visual quality that's indistinguishable from the original at normal viewing distances.
When to Use PNG
- Graphics with transparency — logos, icons, overlays
- Screenshots and UI elements — sharp text and edges
- Images with flat colors — illustrations, diagrams
- Lossless quality requirements — archival or editing workflows
PNG vs Other Formats
For photographs, JPG compression typically produces smaller files because JPG is designed for continuous-tone images. For modern web use, WebP offers the best of both worlds — smaller than both PNG and JPG with transparency support. If you're working with Apple device photos, you may need to handle HEIC files as well.
Your Privacy Matters
Unlike server-based compressors like TinyPNG or iLoveIMG, Compresso processes your PNG files entirely in your browser. Your images are never uploaded to any server — they never leave your device. This makes Compresso the safest choice for compressing sensitive screenshots, proprietary graphics, or any images you don't want on someone else's server.
Related Tools
- Compress JPG — for photographs and continuous-tone images
- Compress WebP — for modern web-optimized images
- Convert PNG to JPG — smaller files without transparency
- Convert PNG to WebP — best web format
- Bulk Compress — process hundreds of images at once
- Compress for Web — optimize images for website performance
Frequently Asked Questions
Does compressing PNG reduce quality?
Compresso uses smart compression that minimizes visible quality loss. At 80% quality, most images look identical to the original while being significantly smaller.
Is PNG compression lossless?
PNG supports both lossless and lossy compression. Lossless compression reorganizes data without discarding information. Lossy compression (like converting to JPG/WebP) achieves much better size reduction by selectively discarding data the human eye is less sensitive to.
What's the maximum file size I can compress?
Since everything runs in your browser, the limit depends on your device's memory. Most devices handle files up to 50MB easily.
Does Compresso remove PNG transparency?
No. Compresso preserves the alpha channel (transparency) when compressing PNG files. If you convert to JPG, transparency is replaced with a white background.
How does Compresso compare to TinyPNG?
Both tools compress PNGs effectively, but Compresso processes everything in your browser — your images never leave your device. TinyPNG uploads files to their servers for processing.
Can I compress multiple PNG files at once?
Yes! Compresso supports batch compression. Upload multiple PNGs and compress them all simultaneously, then download individually or as a ZIP.
Should I use PNG or WebP for my website?
WebP offers 25-35% smaller files than PNG at equivalent quality and supports transparency. However, PNG has universal support and is required for some use cases like favicons. Consider converting to WebP for general web use.
Are my PNG files uploaded to a server?
Never. Compresso uses client-side JavaScript to compress images entirely in your browser. Your files are never transmitted over the internet — they stay on your device from start to finish.
Last updated: March 2026