Beginning with ImageMagick v6.7.9 colorize applies the fill to alpha channel. Previous IM versions did not apply fill to alpha channel with colorize operator. This affects the makeFlash.sh script which uses the following: convert $src -fill white -colorize ${p}% -transparent-color white $t.$p.gif

This is resulting in the transparent background being changed to white. When colorize is applied at 60% and 80%, the background switches to grey/black, making the animation unsightly.

The following link has more info on the colorize operator and its implementation change starting with ImageMagick v6.7.9: http://www.imagemagick.org/Usage/color_mods/