Compress PNG Online - Preserve Transparency, Reduce File Size by Up to 80%

The PNG transparency problem nobody talks about

PNG became the go-to format for UI design because of one feature: alpha transparency. But that same transparency is why PNG files are so large - and why compressing them wrong destroys the transparent edges.

Every online PNG compressor that uploads your file processes it on a generic server using one-size-fits-all settings. FastCompressor analyses each PNG's specific palette and alpha channel before choosing the compression strategy. Logos with flat colours get palette quantization. Photographs saved as PNG get dithering. UI exports with gradients get a different approach entirely.

The result is transparent PNGs that are 60-80% smaller - with edges that remain clean at every zoom level.

For Figma and Sketch users: When you export frames as PNG, Figma defaults to the highest quality setting. These files are enormous. FastCompressor's browser tool handles exported PNGs from both tools without the edge fringing that other compressors introduce.

For web developers: Large PNGs are one of the leading causes of poor Core Web Vitals scores. Google's Lighthouse tool flags unoptimised images as a direct performance issue. A 400 KB PNG icon compresses to under 80 KB without visual change - that's 0.3 seconds of page load time recovered per image.

For Shopify merchants: Product images saved as PNG (for background transparency) are often 2-5 MB each. Compress them to under 500 KB and your store's PageSpeed score improves measurably.