Regarding one of the image's tags, I... don't really see a diaper anywhere; Illya's wearing white panties with a yellow waistband, Kuro's in green panties (that look a bit small on her), Miyu's in slightly girly/frilly-looking white panties...
Taking the common sense approach, visuals aside, this is official art. It wouldn't make any sense whatsoever to have that tag. I went ahead and removed it.