Install png files that is linked from whizzytex.html See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=787799 ===================================================================
See https://github.com/koalaman/shellcheck/wiki/SC2028, https://github.com/koalaman/shellcheck/wiki/SC1004 and https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=772388