Deppends really on what butterfly. And just how realistic you aim for.
Its just that making it look perfect is a bit hard see thing is i used to collect butterflies, and i can tell you that the average butterfly wing has some super crazy shading effects on it. Firts its actually maade of very small hexagonal pieces. Second their color refracts and reflects color like crazy. Then you have all kinds of thin layer diffraction stuff on them for certain species.
go out and photograph one. Thersa a nasty trick pro photgraphers use for this (but i usually frown at this technique), they buy cold spray, and now spray the butterfly with it this forces it to land and recharge heat very close by. Its then easy to shoot, sometimes it homes on your habnd simply because your warm.
Also please not that butterflies have 3 distinctly different modes of flight, and their erattic common flight movement is caused by the fact that a butterfly gains height by closing its wings which sounds a bit counter intuitive.