I like the idea of having a window in the bathroom, but I hate the mildew and water damage. This is a great idea with having a shower curtain over the window while in use, but open the rest of the time.
Put a gallery wall in an unexpected place. Like over the tub in a bathroom in this photo from The Fashion Medley. In your laundry room. In your master closet. Why should the joy of a gallery wall only be for those who enter your common rooms?