The best finish for your tiles is the baked on glaze that tile has, but it is possible to paint the tiles with an epoxy paint and have a virtually maintenance free finish.

A good reference for this project is an article submitted by Simon Phillips called <a href="https://www.house-painting-info.com/article-simon_phillips-painting_bathroom_tiles.html">Painting Bathroom Tiles</a>. The main points to pay attention too are the prep and your choice of epoxy to use. Personally, I would use the best epoxy paint you can afford for this project.

Give the article a good read and let me know if you have any questions.