Tiles can be painted but the prepration and then the application takes a bit if time...
1) Remove all the grout from between the tiles.
2) Clean the tiles throughly.
3) Repeat 2)
In Australia there is a product called Penetrol which is, essentially, paint oil - or paint with no pigment. It cost about Au$12/litre. It claims that it makes (oil) paint stick to anything - and it does.
4) Apply this to the tiles.
5) Wait for a few days for it to harden.
6) Add 10%-20% Penetrol to the Oil paint you want to apply to the tiles and paint away!! Two coats may be needed.
7) Wait for a few more days for the and then grout in the usual way.
But remember, that this ONLY paint and so will only have the durability of paint and not ceramic tiles. Hope this is of help...
