I had "green" ceramic tile in my kitchen for many years, and always believed that it could not be succesfully painted. Wrong!!!
Go to Sherwinn Williams and buy a quart of their X-I-M Sealer/Bonder. Clean the tile with Trisodium Phosphate ( TSP ), also at SW, and apply the sealer/bonder. You can then paint the tile with any good enamel ( I recommend and epoxy ), and it will last for many years.
The X-I-M dries quickly and does not spread easily, so practice with it and use a good stiff foam brush.