fix slideshow controls contrast, remove duplicate code (cherry picked from commit 110184d)
fix slideshow controls contrast, remove duplicate code
(cherry picked from commit 110184d)

patman15/galleryplus,efueger/galleryplus,patman15/galleryplus,leftees/galleryplus,leftees/galleryplus,efueger/galleryplus,patman15/galleryplus,leftees/galleryplus