.caja img {
    width: 220px;
    height: 300px;
}

.caja1 img {
    object-fit: cover;
    
}

.caja2 img {
    object-fit: contain;
   
}

.caja3 img {
    object-fit: fill;
 
}

.fondo div {
/* Background pattern from LOGO principal */
   background-image: url("images/repeticion.png");
   background-repeat: repeat;
}
header {
/* Background pattern from LOGO principal */
    background-image: 
    url("../images/repeticion.png");
    background-repeat: repeat;
    background-position: 50% 25vh;
    background-color: lightgray;
    /*La siguiente medida es porque no encontre una imagen como la que quieres tu*/
    background-repeat: repeat;
    min-height: 50vh;
   
}