I have the same situation in my main bath, only ours is aqua blue tile. I am redoing the bath, but don't want to replace the tile. There are two ways to go with painting tile, as far as I'm told:

There is a kit you can buy (Home Depot, Lowe's) to resurface a tub or ceramic sink. It costs $30 and is a two stage process using epoxy. You must wear a respirator mask and have very good ventilation. This kit covers one tub or two sinks, approximately 80 sq. ft. You can figure out by the amount of wall surface you have, how many kits you would need.

The other way to go, which is what we will be doing, is to prime the tiles with Gripper Primer (also available at HD) and then paint with a couple of coats of high-gloss latex paint (we are doing white). You might also want to seal it with a polyurethane coat in a gloss finish. If you don't like the glossy look of the original tile you could use a satin or matte finish paint. I think this will be roughly half the cost of two or more kits, which I would need in my bathroom. It will also be easier and safer.

One of the posts here in the Gallery shows a bathroom with painted tiles. That's where I got the idea. I don't remember which one it is, but maybe the person will see your question and respond.