What it does
Oxipng is a multithreaded lossless PNG and APNG optimizer with a command-line interface and a Rust library.
Pass PNG/APNG inputs to the CLI and choose an output file, directory or stdout; dry run reports results without writing. Optimization levels run from 0 to 6, defaulting to 2, with no guarantee that a higher level wins. Use safe stripping for APNG: strip-all removes its animation. Alpha optimization changes invisible RGB values, and scale16 reduces bit depth lossily. Recursive output-directory mode flattens folders. A timeout waits for the current trial to finish rather than enforcing a hard deadline.
Strengths
- Lossless PNG and APNG optimization
- CLI and library integration paths
Watch out for
- Strip-all removes APNG animation; alpha optimization and scale16 can discard source information.
Best for
- Optimizing static or animated PNG assets
Sources
- GitHub - oxipng/oxipng: Multithreaded PNG optimizer written in Rust · GitHub (Oct 26, 2026)
- Oxipng levels, alpha and limited APNG optimization (Oct 26, 2026)
- Oxipng output, stripping and dry-run options (Oct 26, 2026)