oxipng

Losslessly improve compression of PNG files. More information: https://github.com/shssoichiro/oxipng.

• Compress a PNG file (overwrites the file by default):

oxipng path/to/file.png

• Compress a PNG file and save the output to a new file:

oxipng --out path/to/output.png path/to/file.png

• Compress all PNG files in the current directory using multiple threads:

oxipng "*.png"

• Compress a file with a set optimization level (default is 2):

oxipng --opt 0|1|2|3|4|5|6|max path/to/file.png

• Set the PNG interlacing type (0 removes interlacing, 1 applies Adam7 interlacing, keep preserves existing interlacing; default is 0):

oxipng --interlace 0|1|keep path/to/file.png

• Perform additional optimization on images with an alpha channel:

oxipng --alpha path/to/file.png

• Use the much slower but stronger Zopfli compressor with max optimization:

oxipng --zopfli --opt max path/to/file.png

• Strip all non-critical metadata chunks:

oxipng --strip all path/to/file.png