.contenedor-flex-c{     
    display: flex;
    flex-direction: column;    
    align-items: center;
  }
  body{
    background-color: red;  
  }
.contenedor-flex{       
    display: flex;
    justify-content: center;
    margin: 1%;    
    padding: 10%;
    background-color: gray;
    border-radius: 10px;
}

div img{
    border-radius: 20px; 
    padding: 10px;
    margin: 5px;    
}

img:hover{    
    background-color: lightgray; 
    border-radius: 25px;
}
img{    
    width: 300px;
}