I'm thinking of photoshopping the hair of one of my wife's bridesmaids to a natural color...from the iridescent blue that she decided to randomly show up with for our wedding
Why do you want to change her hair color?
She looks too high class for blue hair.
That is wrong to edit your wife's bridesmaid's hair like that. That is her personal style and you should respect it.
It will look better when I am done, trust me.
It may look better to you, but what matters more is the bridesmaid's opinion. It is her hair and it should stay the way she wants it, you have no right to change it without her permission.