Crunch

Crunch provides lossy optimization for PNG files by combining selective reductions in bit depth, color type, and palette with Zopfli DEFLATE compression via pngquant and zopflipng. The workflow targets a substantial decrease in file size while keeping visual degradation modest, as illustrated by benchmark images and similarity scores. Continuous benchmark testing is integrated into the project’s CI, and documentation includes examples for photography and illustration use cases.

The tool is available as a command‑line executable that runs on macOS, Linux, and Windows POSIX environments, a native macOS drag‑and‑drop GUI, and a macOS Finder right‑click service. Installation methods include Make‑based builds, Homebrew, and downloadable DMG installers. Users invoke the command line with file paths, drop images onto the GUI window, or select PNGs in Finder and choose the “Crunch Image(s)” service.

Crunch is positioned for developers and designers who need automated PNG size reduction in scripts, desktop workflows, or macOS file‑management contexts, offering a balance between compression efficiency and acceptable image quality loss.