optipng

Optimize PNG file

$ optipng [image.png]

$ optipng -o7 [image.png]

$ optipng [*.png]

$ optipng -preserve [image.png]

$ optipng -simulate [image.png]

$ optipng -strip all [image.png]

$ optipng [image.bmp]

optipng [options] files...

optipng is a PNG optimizer that reduces file size without losing quality. It recompresses the image data and removes unnecessary metadata.
The tool can also convert other formats (BMP, GIF, TIFF) to optimized PNG.

-o level

Optimization level (0-7, default 2).

Strip metadata (all, exif, icc, etc.).

Preserve file attributes.

Dry run, don't modify.

Output to different file.

Output directory.

Keep backup of original.

Quiet mode.

Verbose output.

Fix corrupt data.

Higher optimization levels much slower. Lossless only - can't reduce beyond PNG limits. Some metadata may be useful. Original file modified by default.

OptiPNG was created by Cosmin Truta to provide optimal PNG compression. It builds on the zlib and libpng libraries, implementing various optimization strategies to minimize file size.

pngcrush(1), pngquant(1), jpegoptim(1), convert(1)