Painting over wallpaper/bathroom tile?

Has anyone done this - can you give me some pointers. Just to make the bathrooms look more appealing I'd like to paint over them WHITE.

My mom did it in her house - do you have to prime it first to treat it w/ anything?

Painting over wallpaper will make a mess, IMO. But it is a quick fix.

The previous owners of our house painted the tiles in both bathrooms. It doesn't help that they chose different shades of baby poo brown but they also didn't do a good job. If you do decide to paint the tile, I'd use something with a glossy finish. The tiles in our house were painted with a matte finish and it looks terrible.

I wouldn't prime unless it's a really dark color that you are changing to white.