According to Vastu shastra, Acharya Indu Prakash tells about the pictures one should not put in their child's study room. Great care should be taken while choosing the photographs for your children's study room. It is because of the way the pictures you will put there, the child's mind will also be engaged in studies accordingly.
You must have heard that children learn very quickly from the things around them, so the kind of environment you give them is going to help them build their personality. Try to put pictures in the study room that give some inspiration.
You can put pictures of the rising sun, pictures of seven horses running, birds flying in the sky, chirping etc.
Apart from this, you can also put pictures or posters of those people who have achieved success in their life on the strength of hard work. But keep in mind that do not put any photos showing violence or sorrow. Also, try to avoid putting up film posters etc.