FIXME: The first palette entry in APNGs appears to be unused and has low bits set...
For some reason, the image optimization tools (optipng, advdef, advpng, pngout) are keeping this palette index present...
Some emulators have RGB(224,224,224) as bright white. This tool adjusts it to RGB(255,255,255). This tool only works properly if the image doesn't have Shadow/Highlight enabled and if it isn't a 32X ROM.