Run optipng[1] with -o7 over all PNG files. Files were only modified if the...

Run optipng[1] with -o7 over all PNG files.  Files were only modified if the optimized version is smaller.  There is no change to the rendering as seen by users.

[1] - http://optipng.sourceforge.net/


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@574456 13f79535-47bb-0310-9956-ffa450edef68