There's something really decadent about a pretty chandelier in a small powder room. It makes the bathroom look less like a bathroom, somehow, and a little more like a place where you'd want to spend a bunch of time reading and drinking and soaking away the day. Your tub might just become your favorite place in the house.
Now here's a bit of a warning: These are inspirational images, and these photos have probably been styled by professionals for the purposes of looking pretty, and not always for actually living in. Sometimes, the chandeliers in these photos are lowered to fit everything in frame, or even removed or repositioned before anyone ever takes a bath. In case you need a reminder: magazine life is not real life. And some of these bathrooms are actually unsafe.
The National Electric Code for the U.S. says that hanging fixtures should be at least 8 feet above the top of the bathtub rim. If that's not doable in your space, consider hanging the chandelier at the center of the room for a fancy bathroom that's luxurious and still up to code.* Or use a non-electrified chandelier; one with candles or that's just decorative. If you do have the required vertical, make sure any lights directly over your wet zone are rated for wet or damp locations.
* Here's an idea: Use a little movie magic and hang the fixture in front of the tub, so it's along the same line of sight from the point of view of a person walking in the room. It'll look like it's above the tub, at first.