Optimize PNG

Squeeze PNG file size. Two modes:

• lossless (default) — oxipng. Byte-identical decode. Always safe.
• lossy — pngquant. Palette-quantised; visible artefacts only on smooth gradients. Right call for web/UI assets.

When to use

• Web-prep: PNG screenshots, UI assets, illustrations destined for upload.
• Archival: shave a few hundred MB off a folder of PNG masters losslessly.
• Pre-step inside web-ready orchestrator.

Do not use this skill when:

• Source is JPEG → use optimize-jpeg.
• Source is RAW/HEIC/TIFF → run web-ready end-to-end first.
• Quality must be bit-perfect for cryptographic hashing → only use lossless mode.

Inputs