Losslessly minimize themes’ PNGs
Minimized themes’ PNGs for a space savings of 17%.
Losslessly minimize PNGs as part of build process
Minimize PNGs w/ optipng, advpng, and advdef (these 3 tools compress
better than pngcrush). These 3 tools can be found in the Debian/Ubuntu
packages: optipng advancecomp