optimizegraphics --version (return code: 0)
Please install pngout to increase PNG compression. OptiPNG version 0.7.6 Copyright (C) 2001-2016 Cosmin Truta and the Contributing Authors. This program is open-source software. See LICENSE for more details. Portions of this software are based in part on the work of: Jean-loup Gailly and Mark Adler (zlib) Glenn Randers-Pehrson and the PNG Development Group (libpng) Miyasaka Masaru (BMP support) David Koblas (GIF support) Using libpng version 1.6.32 and zlib version 1.2.11 advancecomp vnone by Andrea Mazzoleni, http://www.advancemame.it
optimizegraphics --help (return code: 0)
Usage: optimizegraphics [FILE] If [FILE] is not defined, it optimizes all files (PNG,MNG,SVGZ) recursively starting at the current working directory. To achieve the best optimization please use all supported tools (optipng,advdef,pngout).