Ancestral pictures are best left on secondary walls if you do not want them to exert too great an influence on your life (this technique was used by my parents, when I live with them).
Hanging paintings of wild animals such as fierce-looking tigers is really asking for trouble, in the same way that displaying paintings of sad or lined faces is harmful (despite I don't believe in Feng Chui, this suggestion it pleases me).
A friend of mine hung a censured painting of a woman above her bed, bringing into her master bedroom the chi energy of another woman’s sexuality (I like this idea, it seems really some positive).