Yes to the one picture. I don’t see the need to over decorate a small bathroom, especial for a man. Most like function and simplicity.

Place one or two hooks on the back of your door to hold bath towels. A simple pleated shade or Roman shade to add softness to the window (and privacy, too!) might be nice. Your picture seems appropriate in size and color, too.

I think the art over the toilet will look nice. But it probably won't make the space feel more "warm" if it feels cool to you. All of the materials in the space are cool-toned and combine that with the hard surfaces in a bathroom and your bathroom will likely have a "cool" feel. But I like it just how it is. It also seems fresh, clean, and up to date.

thank you to everyone!