zopflipng 命令

常用示例

说明

zopflipng optimizes PNG files using the Zopfli compression algorithm, which produces deflate-compatible output that works everywhere standard PNG files do. It typically achieves 3-8% smaller files compared to standard PNG optimization tools. The tool strips metadata chunks by default for maximum size reduction, though specific chunks can be preserved with the --keepchunks option. A lossy transparency mode (--lossy_transparent) further reduces file size by optimizing invisible fully-transparent pixels without any visible quality change. zopflipng is intentionally slow, trading compression time for smaller output. It is designed for final-stage optimization in build pipelines rather than interactive use. The -m flag enables additional iterations for even better compression at the cost of more processing time.

参数

-m

Compress more: use more iterations (slower but better compression).

-q

Quick mode, less thorough compression.

-y

Allow overwriting the output file.

--iterations _N_

Number of iterations for compression (default: 15 for small files, 5 for large files).

--lossy_transparent

Lossy optimization of fully transparent pixels for smaller file size.

--keepchunks _CHUNKS_

Comma-separated list of metadata chunk names to preserve (e.g., iCCP,sRGB).

--keeptime

Keep the original modification time of the input file.

--filters _TYPES_

Filter strategies to try: 0-4, m (minimum sum), e (entropy), p (predefined), b (brute force).

--prefix _PREFIX_

Add prefix to output filenames (may contain a directory path).