"You are small."
Translation:Vy jste malé.
That is also acceptable. The "VY" here can mean many things. You a male i am talking to, you a female, you an it (a child), VY a group of males or VY a group of females.
The one in the "main! translation is me addressing a group of females.
Vy jste malý = single male, formal addressing Vy jste malá = single female, formal Vy jste malé = single neutral formal or multiple female only group Vy jste malí = multiple male or mixed group