Run the icons through ImageOptim

aegisub/src/bitmaps/button/about_menu_16.png

aegisub/src/bitmaps/button/about_menu_24.png

aegisub/src/bitmaps/button/about_menu_32.png

aegisub/src/bitmaps/button/arrow_down_16.png

aegisub/src/bitmaps/button/arrow_down_24.png

aegisub/src/bitmaps/button/arrow_down_32.png

aegisub/src/bitmaps/button/arrow_down_stop_16.png

aegisub/src/bitmaps/button/arrow_down_stop_24.png

aegisub/src/bitmaps/button/arrow_down_stop_32.png

aegisub/src/bitmaps/button/arrow_sort_16.png

aegisub/src/bitmaps/button/arrow_sort_24.png

aegisub/src/bitmaps/button/arrow_sort_32.png

aegisub/src/bitmaps/button/arrow_up_16.png

aegisub/src/bitmaps/button/arrow_up_24.png

aegisub/src/bitmaps/button/arrow_up_32.png

aegisub/src/bitmaps/button/arrow_up_stop_16.png

aegisub/src/bitmaps/button/arrow_up_stop_24.png

aegisub/src/bitmaps/button/arrow_up_stop_32.png

aegisub/src/bitmaps/button/assdraw_16.png

aegisub/src/bitmaps/button/assdraw_32.png