pngquantPNGQuant is a command-line utility and library for lossy compression of PNG images, reducing file sizes significantly (often around 70%) while preserving full alpha transparency. It uses high-quality palette generation with a modified median-cut quantization, adaptive dithering, and premultiplied alpha, plus a fast mode suitable for real-time or bulk processing and easy integration with scripts, GUIs, and server-side software. The project is open-source (Rust and C99 implementations) and hosted on GitHub, with additional tools and plugins such as ImageOptim and SuperPNG.