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/

Reprocess .png's as transparent (w/ GraphicsMagic since my local copy of ImageMagic creates garbage transparent .png's). PR: 30190

First step at stamping out gif's: convert them to png